(Received December 14, 1970; accepted for publication March 1, 1971.)
ADDRESS FOR REPRINTS: (C.H.V.) War Memorial Children’s Hospital, 39Z South Street, London 15,
Canada.
PEDwriucs, Vol. 48, No. 4, October 1971
583
THE
GROWTH
AND
DEVELOPMENT
OF
FOUR
XYY
INFANTS
G. H.
Valentine, M.B., M.R.C.S. (Eng.), F.R.C.P. (C), Marilyn A. McCIeIland, M.A., andF. R. Sergovich, PhD.
From tile War Memorial Children’s Hoital, Crippled Children’s Treatment Centre and
Children’s Psychiatric Research Institute, London, Ontario
ABSTRACT. Four XYY infants ascertained from 1,066 unselected newborn infants have been
followed for 23 to 35 years. None of them show any distinctive physical characteristics, though
three of the four lack a C triradius in the palmar
dermatoglyphics. All four are of normal stature. Three appear of normal intellect and personality.
One is of borderline intelligence and by 2 years
was exhibiting aggressive, defiant, and destructive
behavior.
There are great problems of what, if anything,
to divulge to the parents when an XYY
chromo-some complement has been discovered. Pediatrics,
48:583, 1971, CHROMOSOME ABERRATION, XYY,
NEWBORN INFANTS, GROWTH, PERSONALITY,
COUN-SEXING.
LTHOUGH Sandberg and his co-workers
in Buffalo, New York, discovered in
1962’
(
while seeking a cause for hishay-ing fathered four children with severe
con-genital defects
)
an apparently normal malewith
XYY
chromosome complement, nogreat interest in this chromosome
constitu-tion was aroused until the recognition by
Casey
et
al.2 of its association with delin-quent or criminal antisocial behavior andthe further recognition by Jacobs and her
colleagues of its association with tall
stat-ure. Thereafter interest became intense.
Owing, however, to the tedium and
cx-pense of the full chromosome analyses then
necessary to detect an extra Y chromosome,
searches for males with this anomaly were
conducted (certainly with fruitful results)
almost entirely among those in whom it was
most likely to be found : unusually tall
males in security institutions for those
cx-hibiting antisocial behavior. The frequency
with which the anomaly was found among
the inmates of these institutions gave rise to
the widespread and somewhat uncritical
belief that the XYY chromosome
comple-ment was necessarily associated with a life
of deviant behavior and crime. But, “The
legal implications demand that this conclu-sion should not be accepted hastily.”4
A
true perspective of the sigiiificance ofthe XYY complement could be gained in
several ways. Large studies of unselected
adult males would reveal how many normal
males with the XYY constitution are
unrec-ognized in our midst. The reporting of such
normal males as have been discovered by
chance’6 also would help to redress the
balance of belief. A prospective and
long-term follow-up of the physical and mental
development of XYY males ascertained at
birth in an unselected population of
new-born infants would best indicate the true
significance of this chromosome anomaly.
Clearly information derived in this last
way must await the identification of
appre-ciable numbers of XYY babies from barge
surveys, and their surveillance over at least
two decades. Nevertheless, because the
xYY
complement has been reported79 asbeing associated with physical
abnormali-ties which might be recognizable at an
early age and with abnormal mentality and
personality which has been recognized in
early childhood,’0’1’ it seems appropriate
now to record the growth and development
over the first 23 to 3% years of the four
XYY
newborn infants ascertained in theun-selected survey of Sergovich and his
584
XYY INFANTSand March, 1968 and to indicate also some
of the problems presented by a follow-up of
such randomly ascertained XYY babies.
CASE REPORTS
These four babies were discovered during the
course of a study of the human chromosome
com-plement at birth in which 2,081 successful cultures
of peripheral blood lymphocytes were made from
2,159 consecutively born babies in an obstetrical unit handling predominantly normal obstetrical pa-tients from an urban population together with some problem cases referred from a largely rural
area in southwestern Ontario. The 1,066 successful cultures from male babies identified six examples
of major chromosome abnormality: four XYY, one
xxY, and one D/D Trisomy.
Case 1
J.W. was born April 27, 1967. His mother, aged 28 years at the time of his birth, had had severe
jaundice at 9 years of age, an upper gastrointesti-nal x-ray examination for suspected peptic ulcer in
1962, and pelvic x-rays during the pregnancy of
J.W. Her first child, a male born in January, 1964, is
clinically normal. The second pregnancy resulted
in an 1,800 gm female premature baby who died
of the respiratory distress syndrome at 1 day of
age.
The last pregnancy, J.W., was managed with a Shirodkar operation at 4 months of age and hy-droxyprogesterone caproate from the fifth month to term. The delivery was normal 10 days before the
calculated expected date; birth weight was 3,190 gm.
The father (a highly intelligent school teacher
with an interest in biology) was aged 29 years at
the time of the birth. As a child he had had chorea
and rheumatic fever, has a positive tuberculin skin
test without evidence of active tuberculosis, and
has had annual chest x-rays for several years.
Baby j.W. was group 0 rhesus positive ( mother
group 0 rhesus positive) with a negative direct
Coomb’s test. The crown-heel length was 51.7 cm
and the head circumference was 33.7 cm. The penis, while rather small, was within normal limits.
Both testes were descended. No physical defec
were fouid.
Two days after birth slight jaundice was noted. By 5 days the bilirtibin reached a peak of 16.8
mg/100 ml and stayed at about this level for 2
more days. This jaundice was considered to be
yin-usually severe and prolonged in the absence of
de-monstrable blood group incompatibility.
When the chromosome complement was known
it was judged at that time that it would be quite
unwise, in the absence of certain knowledge as to its significance, to divulge the chance finding of
the XYY anomaly to the parents, though it was
recognized that this was a questionable decision.1’
The family practitioner was informed of our find-ings and of the limits of our knowledge and
ignor-ance in the matter. The baby was discharged
making good progress. The parents were told that
he had “been included in a survey of normal new-born babies and that we would like to follow his
growth and development for our research records.” His subsequent growth in weight and length is shown in Figures 1 and 2.
At 10 months of age and 76.5 cm in height he
appeared a perfect specimen. His parents reported that he had smiled in recognition at 6 weeks, had held his head and chest from the floor at 2 months, had sat alone at 7 months, crept at 7 months, and was now standing holding on and coasting around his playpen. His mother stated that he was bigger
than his brother at the same age, but was of the
same temperament: a happy, contented, cheerful baby.
At this examination the father became suspicious
that we had more than a casual interest in his baby
and questioned whether some abnormality had
been found. He was then told that “an unusual feature had been found in the blood cells, that its
significance was unknown, but that we had every reason to believe that it was compatible with
nor-mal health.” This, for the moment, seemed to
sat-isfy him. A week or two later he telephone to
enquire if we had, in fact, found a chromosome abnormality. The answer was, “Yes.” Some time
later he telephoned again to ask if a Y chromosome had been found in excess. The answer had to be
“Yes.” At this point a full exposition of the nature
and function of chromosomes in general and of the state of our knowledge of the Y chromosome in
particular was given. This made subsequent
exami-nations and interviews easier. Karvotvpes were made on the blood of the father and a male sib-ling; both were normal.
At 14 months of age he appeared a healthy baby of 11.79 kg and 79.3 cm with a most cheerful, pleasant disposition, waving bye-bye, playing
pat-a-cake, saying mamma and dadda, and exhibiting normal curiosity. Because of the report’4 of abnor-mal electrocardiogram features in XYY males, an
E.C.G. was done. It was normal.
At just 2 years of age he was seen again. The parents reported entirely normal development and
behavior, stating that they could not see any
differ-ence in temperament from his brother. The mother
admitted to anxieties about disobediences and re-bellious behavior that, had she not known of his
97#{176}!.
18
16
14
12
10
8
6
Weight
and Age
4
2,
Psychological Evaluation
One of the authors (M.A.McC. ) reported a
chubby, happy child, with normal attention span.
After 2 hours of dermatoglyphic printing, photog-raphy, and psychomotor testing, he showed no
signs of ill temper or aggressive behavior. He was
an exceptionally affable, outgoing child.
Various aspects of his intellectual function were
all near the same level except for expressive lan-guage which was not quite at a 2 year level.
Ver-U)
E
C
+1
I
585
bal comprehension appeared average. Fine psycho-motor skills were close to the 23 year level, whereas
gross motor performances were close to 2 years.
(
1) Stanford-Binet Intelligence Scale, formL-M: 1.9. 106
(
2) Bayley Scale of Infant Development:(a ) Mental development index: 98
(
b ) Psychomotor development index: 111(
c ) Infant behavior record: normal(
3) Vineland Social Maturity Scale: 2-23 yearsBaby J.W. was found to be a happy, cooperative
Age
In months
FIG. 1. Weight gain of J.W., J.G., D.H., and P.M. against scale derived from Boston Children’s Medical Centre Anthropometric Chart of Harold C. Stuart
1001
90
80
60
Lying
Length
and Age
586
xYY
INFANTSU)
E
C C U C
C
110 n
40
‘ ru i i ni i i ri ii 1 fli ii I hi ii 1 1 1
.
4
2024IE364OAge
inmonths
FIG. 2. Linear growth of J.W., J.G., D.H., and P.M. against scale derived
from Boston Children’s Medical Centre Anthropometric Chart of Harold C. Stuart and associates.
lad of average intellectual function who was prob-ably not as aggressive as most 2-year-olds.
Dermatoglyphic Analysis
Dr. H. Soltan reported: The patterns on the digits and hallucal areas are not unusual in form or
frequency of distribution; the total digital ridge count is 140. The C triradiu,s is absent from the
left palm and abortive on the right.
At just 3 years the parents were entirely satisfied concerning temperament, intellectual development, toilet training, and physical growth, but reported
speech to be very indistinct, expecially in “s” and
“j” sounds. Weight was 15.88 kg, height 95.2 cm,
and head circumference 50.8 cm. This is a normal, healthy child.
Speech Therapist’s Report
Mrs. C. Fowler reported: This little boy’s speech showed almost total omission of all
conso-nant srnnd.i. Consequently, it would be difficult to recognize any organic-type signs had they been present. On occasion syllable reversal was queried. Comprehension of verbal material was adequate
f
or general conversation.Becau.se of unintelligible speech, language struc-ture was difficult to assess. It seemed somewhat immature, but not seriously so.
Tongue movements seemed somewhat sluggish, but not apraxic. J.W. was able to make most con-sonant sounds in isolation.
587
Screening Unit,#{176}was within normal limits in the right and down 15 db in the left ear. This slight loss would have no bearing on his speech problem.
It is recommended that J. W. attend Crippled Children’s Treatment Centre Nursery School four afternoons a week and receive speech therapy in conjunction with the Nursery School program.
Because other workers with similar studies had indicated their indecision as to what to tell parents under these circumstances, these parents were now
asked their reaction to the knowledge of their child’s abnormality. They both agreed that they would have preferred to have remained in igno-rance, for, they said, one could not but worry.
They said they would have preferred to have been
told that he was a participant in a routine survey
of norma! babies. They were reminded that this was just what they had been told, but that it was
their curiosity and suspicion that had revealed the
truth to them. The father then said that he would not have been suspicious had it not been for the
fact that he had been reading biology and was
aware of the relationship between x-rays and chro-mosome abnormalities; and his wife had had
ab-dominal x-ray examinations. He felt that once his
suspicions had been aroused it would have been
wrong, then, to conceal the truth and to withhold detailed discussions of our knowledge of the XYY
constitution.
Follow-up of J. W., now aged 3 years, 4 months, will continue.
Case 2
J. C., was born June 3, 1967. His mother, aged
21 years at the time of his birth, had had a previ-ous pregnancy in 1963 with a phenotypically nor-mal male child. There had been no miscarriages. She had had occasional chest x-rays and had been x-raved several times in childhood for shoe-fitting
by shoe-store x-ray apparatus. The father, aged 32
years, had been x-rayed several times after an an-tomobile accident in 1965.
The pregnancy was complicated by mumps at
the sixth month. The delivery at term was normal with a birth weight of 3,090 gm, a length of 49.0 cm, and a head circumference of 36.6 cm. No
din-ical abnormality was found. At 3 days slight and
quite transient jaundice was apparent and slight,
but normal breast enlargement developed.
As soon as the karyotvpe was known the family
practitioner was informed. Because the mother was
of a worrying disposition and very nervous he re-quested that no mention be made of any unusual findings in the baby. Follow-up was contrived by telling the parents that the baby had been included
in a study of jaundiced newborn infants. Because of the mother’s nervous disposition it was felt that
the baby should not be examined too frequenfly. At 8 months his mother reported excellent
prog-0 Zenith Radio Corp., Chicago, Ill.
ress. He smiled and recognized, she said, at the “usual time,” reached out for objects at 3 months, sat alone at 6 months, was attempting to pull him-self to standing, and was exploring everything with
his mouth. She stated that he was a very happy, contented baby. This he indeed seemed to be. The
weight was 8.40 kg, lying length 69.9 cm, and
head circumference 45.4 cm. There were obvious, but not abnormal, epicanthic folds. The penis was small, but within normal limits. Both testes were descended. Subsequent growth is illustrated in
Fig-ures 1 and 2.
At 16 months of age the mother reported that he was bigger than his sibling at the same age, that he had a huge appetite, but was similar to his sib-ling in intellectual progress and temperament.
Ex-amination showed a happy, normal baby of 10.42
kg, and 77.5 cm, lying length with a head
cir-cumference of 47.6 cm.
His mother reported that she had been discov-ered to have Hodgkin’s Disease since her last visit, but that she was continuing to work full-time as a typist and that J. C. had been cared for by a very reliable babysitter since he was 9 months old.
At just 2 years of age he was seen again and
appeared entirely normal. Weight was 11.24 kg, ly-ing length 83.8 cm, and head circumference 48.5
cm. He appeared of an exceptionally happy dispo-sition.
Psychological Evaluation at 24 Months
J. C. reported as a cooperative, outgoing, 2-year-old with a normal attention span. Toward the end
of testing he tired somewhat and then failed to
perform one or two items on the Baylev Mental
Development Index which were very similar to the Binet items that he had successfully accomplished.
(
1) Stanford Binet, form L-M : I.Q. 102 (2 ) Bayley Scales of Infant Development:(a ) Mental Development Index: 93 (b) Psychomotor Development Index : 105
(
c) Infant Behaviour Record : normal(
3) Vineland Social Maturity Scale: 2-23 yearsJ. G. reacted to frustration with more aggressive behavior than J. W., but still in a mild manner
for a 2-year-old. He was a well adjusted boy of
average intellectual ability, probably less aggres-sive than most 2-vear-olds.
Dermatoglyphic Analysis
The digital patterns are not unuiual except in the low total ridge count of 88. The C triradiuc is absent from the left palm, but is normal on the right. The axial triradius is absent on the right. Both hallucal areas bear Arch Proximal patterns.
At 35 months of age, his mother having died of
Hodgkin’s Disease 4 months previously, he was
brought by his grandmother for examination. Dur-ing the daytime he was cared for by the same
588
XYY INFANTSgrandmother who reported him as “very smart for
his age,” to be speaking very clearly, to be neat-fingered and well coordinated, but to be rather bossy of his 6-year-old sibling who is smaller and less robust.
On examination he was screaming, rebellious, and negativistic, but not exhibiting abnormal beha-viour. Weight was 12.69 kg and length lying 92.7 cm.
His grandmother who, not surprisingly, was over-indulgent, was not told of any abnormality. Follow-up will continue.
Case 3
D. H. was born August 6, 1967. His mother was aged 18 years, unmarried, and of average
intelli-gence. She had had no unusual sicknesses and no
irradiation. The father, aged 17 years, was not
available for study. He was stated to be still part-time in school in grade 10 (equivalent to the
edu-cational standard of average 14 year old ) and
work-ing part-time as an elevator operator. He had had
gonorrhea at age 15 years and 17 years. The hospi-tal records on one of these occasions describes him
as “alert and intelligent.” He has a retarded sibling
(
not investigated ) and a schizophrenic mother.The pregnancy and delivery of D. H. were
nor-mal and at term; birth weight was 3.240 kg, length 50.8 cm, and head circumference 36.9 cm. He ap-peared normal in every respect. In addition to the
peripheral blood leucocvte culture, fibroblast
cul-hire from the circumcised foreskin also showed an
xYY
complement.The mother of D. H. was living with her mother
and at first elected to keep the baby. Nothing was
revealed at that time about the chromosome anom-aly. Follow-up was arranged with the City Board of Health Well-Baby Clinic. His mother proved to
be wayward and quite unreliable, often leaving
home for unknown destinations while D. H. was cared for by his grandmother. Follow-up was
diffi-cult, but at 5 months of age he was seen at the
Well-Baby Clinic, but not examined in detail.
Weight was 6.54 kg. Growth is illustrated in Fig-ure 1.
At 10 months he weighed 10.14 kg with a lying
length of 77 cm. He appeared an extremely
healthy and entirely normal baby. In an attempt to ensure adequate follow-up the grandmother was told that we had “found something in the blood cells which is sometimes found in the blood of those who have mental problems.” She seemed
nfl-concerned by this.
At 13 months he was brought for examination by his own mother who had returned from her
wan-derings. She reported D. H. to be “smarter than
average,” feeding himself neatly with a spoon, waving bye-bye, playing pat-a-cake, walking alone and saying mamma, dadda, tata, and hiya.
Al-though she reported him as usually a happy baby
she said that he had a “real bad temper.” If frus-trated he would bite, kick, and pull her hair. Be-havior and physique appeared normal on examina-tion. Weight was 10.76 kg, lying length 81.9 cm,
and head circumference 46.4 cm.
Electrocardio-gram was normal.
At 15 months, his mother having again disap-peared and his grandmother being unable to look after him, he was placed in a foster home as a tern-porary ward of the Children’s Aid Society’. After a month he was moved to another foster home where an experienced foster mother reported his behavior
as normal.
At 19 months his weight was 12.25 kg, lying length 84.4 cm, and head circumference 48.4 cm.
At 2 years he was in yet another foster home where he was described as being very stubborn and determined, “like a rock.” “His extreme defiant temper is amazing for a 2-year-old.” If frustrated he would throw things, bite other children, and even adults. “If he wants the toys of other children he must have them.” He liked to climb to high places, had a very large appetite, and would often eat dirt, gravel, and soap. Weight was 12.85 kg,
lying length 89.5 cm, and head circumference 49.0 cm.
Psychological Evaluation at
2
years 5 daysWhen tested he had a bad cold and cough and
had been awake most of the night. He had been
emotionally upset by an altercation, in his pres-ence, between his mother and the Children’s Aid
Society caseworker. The results are open to ques-lion.
(
1 ) Stanford Binet Intelligence Testing, form L-M: I.Q. 84(2) Bayley Scales of Infant Development:
a ) Mental Development Index: 81 b) Psychomotor Development Index: 90
c ) Infant Behaviour Record : cooperation was
only minimal. His attention span seemed
short at times and physical behavior hy-peractive. Language heard at this time
and as reported by the caseworker is not at a 2 year level. He is, according to ac-counts, demanding, and reacts to frustra-lion of his wants by temper tantrums, bit-in, hitting, and throwing things. During the testing situation he was not so
aggres-sive as described.
(3) Vineland Social Maturity Scale: 2 to 23
years.
It is not possible to be certain that this aggres-sive and undisciplined behavior is not the result of his very unsettled background. One would like to see him again after some months of calm,
ARTICLES
Dermatoglyphic Analysis
The digital patterns are not unusual. The total
ridge caunt is 191 . The triradius is absent from the left palm but present on the right.
When seen again at 2 years 4 months, he was in
the same foster home. The foster mother described him as very smart and intelligent, but of “uncanny obstinacy.” “You have to be careful never to give him an order because that ensures that he will not
do what you want.” The biting of others and of
himself when frustrated had continued, though per-haps less violently. He continued to eat cosmetics,
twigs, leaves, gravel, ashes, cigarette butts, bugs and insects and dog excrement. He drank liquid
detergent when he could get it.
On examination he was a happy, cheerful,
coop-erative and very charming, handsome boy. Weight was 13.8 kg, lying length 92.65 cm, and head
cir-cumference 49.0 cm. There was no physical
abnor-mality. The electroencephalogram was normal.
At 2 years 9 months the same foster mother de-scribed him as quietening down, though he still
seemed “deliberately destructive, throwing food on the floor, flying at other children with teeth and
claws and really battling to get their toys.” He was sleeping very well, showed no clumsiness or in-coordination, but his speech was described as slightly indistinct and babyish, though he talked volubly.
Psychological reevaluation, age 2 years 9 months
Although one is not really happier about the
re-liability of testing than one was 9 months ago, there are now more clearly a number of areas of
serious concern. D. fails the language items at the 2-year-old level of the Binet. Recognition
vocabu-lary, as estimated by the Peabody Test, is near a 2
year level. Poor verbal comprehension may account
for failure at some items of the Bayley Scales for
which he seemed to have the necessary manipula-live skills.
Although generally cooperative, there were some
tasks he refused to attempt. He was most
respon-sive to objects that he could manipulate with his hands, but attention span was poor in looking at
pictures.
He is able to string beads nearly as well as a
3-year-old. His grasp of a crayon is somewhat imma-ture for his chronological age, but there is no
atax-ia or tremor. Grosser muscle activities do appear
somewhat slow and awkward, but variability is great at this age.
(
1 ) Stanford Binet Intelligence Scale, form L-M: I.Q. 82(
2) Bavley Scales of Infant Development:(a) Mental Development Index: less than 76
(b) Psychomotor Development Index: 76
(
c) Infant Behaviour Record: See above (3) Vineland Social Maturity Scale: 2-3 years(4) Peabody Picture Vocabulary Test: 76
There was an improvement in the aggression,
al-though this still seems excessive; a worrisome lack of warm interpersonal relationships with peers, and to some extent with adults; pica; slower than aver-age language and intellectual performance; somewhat awkward, incoordinate gross muscle activity.
D.H. remains in the same foster home as a
ward of the Children’s Aid Society. Follow-up continues.
Case 4
P.M. was born January 25, 1968. This was the
first pregnancy of an unmarried mother, aged 20 years. There was no relevant sickness and no
irra-diation. Through the courtesy and efforts of Dr. J. F. Fekety of the Regional Department of Health Laboratory, Fredericton, New Brunswick, a
pe-ripheral blood leukocyte culture was obtained from
the father, a student of apparently superior intelli-gence and normal behavior. The culture was nor-mal.
The baby was born 4 weeks before term by a
Caesarean section because of disproportion with a breech presentation. Birth weight was 3.248 kg, crown-heel length 52.0 cm, and head
circumfer-ence 33.65 cm. His appearance was unusual. There was a rather low, receding forehead, a prominent
occiput, slight micrognathia, a large, but not
beaked nose, and very floppy ears. There was
slight “anti-mongoloid” slant to the eyes. The
mus-des and ligaments were hypotonic and lax : the
skin appeared as though too big for the baby. No other abnormalities were evident. It is thought that his unusual appearance would have caused com-ment, though not necessarily any special
investiga-lions, even had his abnormal chromosome
comple-ment not been known at this lime. His growth is illustrated in Figures 1 and 2.
Since the mother did not wish to keep the baby
he was taken by the Children’s Aid Society as a
temporary ward. They were told of the XYY
con-slitution and of its possible implications. It was felt that the mother also should be told of the reasons that might make for difficulties in placing the baby for adoption.
At 10 weeks he weighed 5.25 kg, with a lying length of 59.2 cm and a head circumference of 39.35 cm. His rather odd facial appearance was still evident. Head control was good for his age
and he smiled and responded readily to handling and voice.
At 14 weeks of age he was taken into the home of a mairied brother of his mother who lives in
another province. This couple have subsequently
590
XYY
INFANTShome. These adopting parents were told in detail
about the abnormal chromosome complement and
of the state of our knowledge, such as it was, of its implications. The pediatrician who would now be
looking after the baby was similarly informed.
For a time contact was lost, but when P.M. was
13 months of age Dr. L. E. Stickles of Fredericton
reported that the development had been normal,
that he was very nearl walking without support,
and had learned eight or 10 words. He measured
his length as 76.9 cm, lying, his weight as 9.30
kg and his head circumference as 45 cm. In a
de-tailed personal letter at this same time his adopting
mother reported him to be a ‘er happy, con
tented, easv-gomg, and lovable baby who was no different in personality from her own three chidren
at the same age. Photographs showed the baby to be of now normal appearance apart from unusually large ears.
At 16 months of age a personal visit to the home
found an entirely normal infant of 77 cm lying length, 10.79 kg. His ears, while large and floppy,
would scarcely be noted at this time as abnormal.
Dermatoglyphic Analysis
There (lC no unusual features of digital, palniar,
or hallucal patterns. The total digital ridge count
is 9.3.
At 22 months of age his mother reported normal physical and behavioral development, mentioning again that she noted no difference in temperament
from her own children at the same age. At 22 months lie weighed 11.75 kg, was 82.6 cm in
length, with a head circumference of 45.7 cm.
Psychological Evaluation
The evaluation at 2 years of age (home visit by
M.A.Mc.) showed a happy, outgoing lad, very responsive to social activities. He had excellent at-tention span. Gross and fine motor coordination
was excellent. He showed less interest and
devel-opment of expressive language than is usual at this
age and no interest in picture books. (The com-plete absence of visible books in this home made one wonder if they were much in use in this house-hold). The family are very interested in sports and P. handles a hockey stick with remarkable effi-ciency.
(1) Stanford Binet intelligence Scale, form L-M:
!.Q.
102(2) Bat,ley Scales of infant Development: (a) Mental Development index: 84 (b) Psychomotor Development index: 105
(
c) infant Behavioral Record: normal (3) Vineland Social Maturity Scale: 2 years +This demonstrates a happy, well adjusted boy with
close to average intellectual function and average
degree of aggrcsiceness.
At 28 months of age his mother again reported
his happy, easy-going temperament, his love of pet
animals, and his excellent speech. His weight was 13.1 kg, his lying length 86.4 cm, and his head
cir-cumference 46.4 cm. His pediatrician confirmed his normal development. His cardiogram showed no abnormality.
Apart from an unusual appearance at birth and continuing disproportionately large ears, he is an
entirely normal child. Follow-up will continue.
DISCUSSION
Although it is riot strictly relevant to this report, the reader will surely wonder if the discovery of four XYY infants in 1,066
unse-lected male newborn infants truly indicates
the frequency of this chromosome
comple-ment at birth. If one adds to this London,
Ontario, series the published surveys of
male newborn infants from Edinburgh,
Scotland,
(
5 in 3,500)
and from Boston,U.S.A. (none in 3,000) one finds nine XYY
babies in 7,566: an incidence of 1:840. If
one further adds unpublished data from
Newhaven, U.S.A. (3 in 2,222), from
Pittsburgh
(
3 in 1,023),
and fromWinni-peg, Canada
(
none in 1,582)
one derivesan incidence of 1 : 826 male infants from
pooled data on 12,393.
The wide differences in incidence cited
above could be explained by geographical
and temporal disparities between the
stud-ies, by variations in technique or by chance.
Even with these wide differences it seems
reasonable to conclude that the incidence
of the XYY chromosome complement in
males may not be much different from that of Down’s syndrome.
That one finds nine examples of XYY
males among 315 institutionalized
delin-quents2#{176} does not of course tell us how
many may be unrecognized in our midst as
adults, nor how many may have died along
the way in infancy and childhood. It seems
legitimate therefore, despite the labor and
expense involved, to conduct surveys of
newborn populations, for it is only by such
prospective studies that one can truly
deter-mine the significance of this and other chro-mosome anomalies.
The recently discovered fluorescence of
the Y chromosome in the leucocytes of a
simple peripheral blood smear stained with
microscopy now makes large surveys much more practical.
It is difficult to know just how to handle
the knowledge that one acquires. If it were
known
(
as it is known with certainty thattrisomy 21 is associated with mental
retar-dation
)
that double representation of the Ychromosome is invariably associated with
criminal behavior, the discovery of that
chromosome constitution would entail fairly
clear-cut responsibilities in counselling
par-ents and in the protection of society. We
have no such certain knowledge about the
YY constitution. That it can be found in
en-tirely normal men seems 5,6 That it
carries an increased risk of anti-social
be-havior likewise seems sure. The public is
well aware of the latter fact, but not of the
former. This being so, it seems best in the
interest of the child to conceal-if one
can-a knowledge of the YY constitution. Can
one imagine a situation more likely to lead
to the abnormal upbringing of a child than that its parents should even think it
possi-ble that it might be predestined to a life of
crime. The parents of J.W. certainly wish
that they did not know.
If the knowledge is to be concealed,
veillance of the child becomes a matter of
dissimulation. One has to invent spurious
reasons for periodic examination, while
be-ing careful not to appear too interested lest
suspicion be aroused. This deceit has been
successfully achieved in the case of J.G.;
not with J.W.
If the facts have perforce become known
to the parents, one must mitigate their
im-pact by repeated
(
and, one believes, true)assurances, that the YY chromosome
com-plement is entirely compatible with a
re-spectable and happy life. One must neither
exhibit too much interest, nor conduct too
much investigation, lest one’s reassurance
be undermined and the child comes to be
regarded with doubts and apprehensions.
For this reason, repeated psychometric
test-ings were omitted and an electroencephalo-gram was done only in the case of D.H.,
who was showing an overt disorder of
be-havior.
D.H. and P.M. presented the problem of
what one should reveal or conceal about a
child who might be adopted. It is our view
that such a case is different from that of a
child whose own parents would have no
op-tion but to take him into their home and
care for him. Adopting parents, in our view,
having the choice of accepting or rejecting
a proffered child, were entitled to know of
our findings and of our knowledge and ig-norance of its implications. Accordingly, the
adoption agency was told the facts, with a
recommendation that they be passed on to
the prospective adopting parents. The
tin-dc and aunt of P.M. were undeterred by
our information and are delighted with
their little boy. D.H. remains unadopted, in
the first place perhaps because his mother
had not decided to relinquish him, and now
because his behavior has become unusual.
Although several reports testify to the
as-sociation of the XYY constitution with
cer-tam physical defects that one would expect
to be detected in infancy, we have found no
such abnormalities. It is true that J.W.
de-veloped hyperbilirubinemia, but
hyperbili-rubinemia without obvious cause can also
occur in babies who certainly are not XYY.
J.G.,
D.H., and P.M. did not show unusual bilirubinemia.None of our babies showed genital ab-normalities, though undescended testes and
genital hypoplasia have been reported by
several authors.s2122 None showed any
in-dication of congenital heart disease, though
such an association with YY complement
has previously been 21, The
electro-cardiograms in J.W. and P.M. did not show
the abnormal features in adults described
by Price.14
Transverse or simian palmar creases were
not seen in our four patients, though they
have been found in other patients with a
YY
chromosome complement. #{176}‘ 26 Thedistribution of digital dermatoglyphic
pat-tems was not remarkable in our patients.
The mean total ridge count of 128 in the
four infants is somewhat lower than the
mean value of 144 from three controlled
se-ries of males examined by Cushman and
Soltan,27 Holt,28 and Uchida, et 29 and is
592
XYY
INFANTS
xYY
men studied by Penrose’#{176} who hassuggested that the total digital ridge count
is inversely proportional to the amount of X
and Y chromosome material in the
chromo-some complement. The variation, however,
of the total ridge counts in our four patients (J.W. 140, J.G. 88, D.H. 191, P.M. 93)
makes the significance of this somewhat low
mean ridge count doubtful. The axis
trira-dius was absent from the right palm of J.G.
but the mean value of the seven atd angles
present in the four patients was 46.9, a not
unusual value and in contradistinction to
the narrow angles noted by Persson31 and
by Spencer, Eyles, and Mason32 in two of
three XYY patients. J.G. has bilateral arch
proximal patterns on the hallucal areas,
pat-terns found on the left foot in 2.8% and on
the right foot in 3.0% of a control Canadian
population.2I
Three of our four infants
(
J.W.,J.G.,
D.H.
)
were lacking the C triradius fromthe left palm, while J.W. had an aborted C
triradius on the right palm also. The C
tn-radius was absent from the left palm in
6.8% of 500 control Canadian males and
from the right in 2.8%. Aborted C tniradii
were found on the left hand in 17% and on
the right hand in 9.4% of 500 controls.2#{176}
While this feature does not appear in other
descriptions of the dermatoglyphics of the
xYY
individuals, and while we report onlyfour cases, the absence of the C tniradius in
three of those four cases may indicate that
this is a common feature in XYY
individu-als.
The dentition of our infants is normal,
though dental abnormalities have been
de-scnibed in other patients.25’33’34
In brief, if one discounts the large ears of
P.M., our four XYY infants are perfect
physical specimens of exceptionally
hand-some appearance and robust physique. So
far none is unusually tall, though rather
surprisingly and inexplicably, J.W. and
D.H.
were at or above the 97th percentilefor length at around 9 months of age. It
may well be as Heinz35 has said “The over
growth which represents the only
symp-toms in all groups
(
he suggests fourpheno-typic variants of XYY
)
does not usuallybe-come present before the end of puberty.”
Time will tell.
Clumsiness, awkwardness, and abnormal
posturing of the hands in childhood has
been noted by several observers of XYY
pa-lients.#{176}’338 Cerebellar tremor was seen in
nine XYY adults by Daly36 who
com-mented, “Although I do not have precise
in-formation regarding the age of onset of
these abnormalities
(
tremors)
in adults, Ithink it would be prudent to look for them
in children.” We have looked and found no
unusual motor phenomena.
J.W. has quite a severe defect in
articula-tion. While one sees many children who at
3 years have equally severe defects, and
while there is nothing specifically unusual
about the defect of J.W., there may be an
association of speech defect with the XYY
chromosome complement as suggested by
Elbualy.11 Dysrhythmic tongue and lip
movements with incomplete
velopharyn-geal closure are noted by Daly,
et al.
Itmay be significant that in our cases the
Mental Development Index
(
measuringin-tellectual development with a substantial
speech component
)
scores lower thanPsy-chomotor Development Index
(
whichmea-sures motor function).
We believe it can be fairly said that J.W.,
J.G., and P.M. are normal in behavior and
intellect; they are not aggressive,
destruc-tive or hard to manage, and they are
excep-tionally affable children. It is difficult to
know how much long range comfort one
can take for this present normal behavior,
for Matthews and Brooks9 report
antiso-cial, impulsive behavior in a 23-year-old
xYIxYY
soldier who in infancy andchild-hood was quiet and unaggressive. On the
other hand, Cowie and Kahn1#{176}and Elbualy
report unmanageable, defiant, destructive,
and aggressive behavior evident by 4% years
of age. In almost all XYY cases where
childhood behavior is recorded, personality
disorder has been noted at quite an early
age. One has, however, constantly to
re-member that reported cases represent a
ARTICLES
deviant behavior. It is to be hoped, perhaps
expected, that J.W., J.G., and P.M. will
pro-gress as normal children into normal
adoles-cence and maturity.
One is much more concerned about the
outlook for D.H., for in the XYY children
reported by Cowie and Kahn’#{176}and by
El-bualy1’ an extremely defiant nature,
de-structiveness, outbursts of temper if
frus-trated, and an inclination to climb to
dan-gerous places had become evident by 4
years of age. However, if one did not know
of the
XYY
chromosome complement in thisboy, one would with every justification
as-cribe his personality defects to an
unsatis-factory heredity on his father’s side and a
most unstable emotional climate for the first
2 years. Perhaps the XYY individual is in a
precarious emotional balance which
re-quires only other inherited personality
de-fects, or an unstable emotional climate to
precipitate the impulsive, aggressive, and
antisocial features that have come to be
as-sociated with a YY chromosome
comple-ment. It certainly seems as though in
in-fancy at any rate, the XYY individual is
comparable to the XXY and the XXX
mdi-viduals who may be perfectly normal, or
who may, for reasons unknown, exhibit
in-tellectual impairment, behavioral disorder,
or both.
\Vhat has one learned from a study of
these four randomly ascertained infants?
No more perhaps than the knowledge that
in infancy there may be no clue, either in
physical characteristics, or in intellectual or
emotional development to the presence of
an extra Y chromosome. Time alone will tell
whether that happy state of affairs will
con-tinue into later childhood and maturity.
ADDENDUM
j.\v.,
j.C.,
DII., and P.M. have now beenfol-lowed to 4 years 3 months, 4 years 2 months, 4
years, and 3 ‘ears 6 months respectively. j.W.,
J.G., D.H., and P.M. continue to show normal
physical growth and development. J.G. and P.M. are normal in all functions. J.W., while of normal intellect and temperament, still has very indistinct speech despite therapy. D.H. now appears less
defiant and aggressive in his foster home. During a
brief period of hospital and hospital nursery school
observation, aged 3 years 8 months, no abnormal
behavior was noted.
Another XYY baby, ascertained by the fluores-cent Y technique and as yet only 4 months old, shows no physical abnormalities.
REFERENCES
1. Sandberg, A. A., Koepf, C. F., Ishihara, T., and Houschka, T. S.: An XYY human male. Lancet, 2:488, 1961.
2. Casey, M. D., Segall, L. J., Street, D. R. K., and Blank, C. E. : Sex chromosome abnor-malities in two state hospitals for patients
requiring special security Nature (London), 209:641, 1966.
3. Jacobs, P. A., Brittain, R. P., and McClermont, W. F. : Aggressive behaviour, mental
subnor-mality and the XYY male. Nature (London), 208:1351, 1965.
4. Suinn, R. M. : YY syndrome and sampling
tech-niques. Lancet, 1 : 157, 1969.
5. Weiner, S., and Sutherland, G. : A normal XYY man. Lancet, 2: 1352, 1968.
6. Stenchever, M. A., and Macintyre, NI. M. : A
normal XYY man. Lancet, 1 :680, 1964.
7. Fraccarro, M., Davies, P., Bolt, M. C., and Schutt, W. : Mental deficiency and undes-cended testes in two males with XYY chro-mosomes. Folia. Hered. Path. ( Milano), 11:
211, 1962.
8. Carakushansky, G., Neu, R. L., and Gardner, L. I.: XYY with abnormal genitalia. Lancet,
2:1144, 1968.
9. Daly, R. F., Chun, R. W., Ewanowski, S., and
Osborne, R. H. : The XYY condition in child-hood. Prrnrrncs, 43:852, 1969.
10. Cowie, j., and Kahn, J.: XYY constitution
in prepubertal child. Brit. Med. J., 1:748, 1968.
11. Elbualy, M. S.: The XYY condition in
child-hood-Clinical observation. PEDIATRICS, 44:
620, 1969.
12. Sergovich, F., Valentine, C. H., Chen, A. T. L.,
Kinch, R. A. H., and Smout, M. S.: Chromosome aberrations in 2159 new-born babies. New Eng. J. Med., 280:851, 1969.
13. Valentine, G. H., and Sergovich, F. : A New
Dilemma. Lancet, 2: 151, 1967.
14. Price, W. j.: The electrocardiogram in males
with an extra Y chromosome. Lancet, I: 1106, 1968.
15. Ratcliffe, S. G., Stewart, A. L., Melville, M. M., Jacobs, P. A., and Keay, A. J.:
Chromo-some studies on 3500 newborn male infants. Lancet, 1:121, 1970.
16. Walzer, S., Breau, C., and Gerald, P. S.: A
chromosome survey of 2400 normal newborn
594
XYY
INFANTS17. Lubbs, H. A., and Ruddle, F. H. : Cited in Ratcliffe, S. C., Stewart, A. L., Melville, M. M., Jacobs, P. A., and Keay, A. J.:
Chro-mosome studies on 3500 newborn male
in-fants. Lancet, 1:121, 1970.
18. Turner, C. D. : Personal Communication to
Marinello, M. J., Berkson, R. A., Edwards,
1.
A., and Bannerman, R. M. : A study of the xYY syndrome in tall men and juveniledelinquents. J.A.M.A., 208:321, 1969. 19. Hammerton, J.: Personal Communication.
20. Jacobs, P. A., Price, W. H., Court Brown,
W. sI., Brittain, R. P., and Whatmore, P. B.: Chromosome studies on man in a maximum
security hospital. Ann. Hum. Genet., 31:339, 1968.
21. Fraccarro, M., Davies, P., Bott, M. C., and Schutt, W. : Mental deficiency and
undes-cended testes in two males with XYY chromosomes. Folia Hered. Path., 11:211,
1962.
22. Sandberg, A. A., Ishihara, T., Crosswhite, L. H.,
and Koepf, G. F. : XYY Genotype. Reports
of a case in a male. New Eng. J. Med.,
268:585, 1963.
23. Rainer, J. D., Jarvik, L. F., Abdullah, S., and Kato, T. : XYY karvotvpe in monozygotic
twins. Lancet, 2:60, 1969.
24. Court Brown, \V. M., Price, W. H., and
Ja-cobs, P. A. : Further information on the
iden-lity of 47, XYY males. Brit. Med. J., 2:325,
1968.
25. Townes, P. L., Zeighier, N. A., and Lenhard,
L. W. : A patient with 48 chromosomes
(XYYY). Lancet, 1:1041, 1965.
26. Mavalwala, J., Parker, C. E., and Malynk, J.:
Dermatoglyphics of the XYY syndrome.
Amer. J. Phvs. Anthrop., 30:209, 1969.
27. Cushman, C. J., and Soltan, H. C. :
Dermato-glyphics in Klinefelter’s syndrome. Human
Heredity, 19:641, 1969.
28. Holt, S. B. : Quantitative genetics of fingerprint
patterns. Brit. Med. Bull., 17:247, 1961. 29. Uchida, I. A., Soltan, H. C., Simpson, N. E.,
Miller, J. R., and Clearwater, K. :
Dermato-glyphics of a normal caucasian population,
unpublished observations.
30. Penrose, L. S.: Finger print pattern and the
sex chromosomes. Lancet, 1 :298, 1967. 31. Persson, T. : An XYY man and his relatives. J.
Ment. Defic. Res., 11 :239, 1967.
32. Spencer, D. A., Eyles, J. W., and Mason, M. K.:
The XYY syndrome and XYY/XXYY
mo-saicism. J. Med. Cenet., 6:159, 1969.
33. Ricci, N., and Malacarne, P. : An XYY human
male. Lancet, 1 :721, 1964.
34. Cowling, D. C., Rigo, S., and Martin, F. I. R.:
The YY syndrome. Med. J. Aust., 2:443,
1969.
35. Heinz, H. A. : YY-Syndrorne forms. Lancet, 1: 155, 1969.
36. Daly, R. F. : The XYY condition in childhood-Clinical observation. PEDIATRICS, 44:621,
1969.
37. Daly, R. F. : Neurological abnormalities in XYY
males. Nature (London), 221:472, 1969. 38. \lintrer, R., Pergament, E., Berlow, S., and
Sata, H. : The XYY s’ndrome. J. Pediat., 72:
572, 1968.
39. Matthews, M. B., and Brooks, P. \V. : Aggres-sion and the YY syndrome. Lancet, 2:355,
1968.
Acknowledgment
We wish to express our thanks to Dr. H. C. Sol-tan for the dermatoglyphic analyses, to Mrs. Carol
Fowler of London District Crippled Children’s Treatment Centre for the report on the speech of J.W., to Dr. L. E. Slickles of Fredericton for his