Behavioral implications of the human XYY genotype

Disorder of Sexual Development Males With XYY in Blood Have Exactly X/XY/XYY Mosaicism in Gonad Tissues

Y chromosome represents masculinization. The extra Y chromosome of XYY patients usually leads to over-masculinization phenotypes. The occurrence of several DSD cases with XYY in blood is controversial. Is XYY associated with disorder of sex development (DSD)? What is the mechanism behind DSD in males with XYY in blood? To this end, this study retrospectively analyzed blood-karyotype data of 4,437 DSD male children and karyotypes data of 6,259 newborn males as the control. Exome sequencing (ES) was performed to test whether the patients with DSD and with XYY in blood had other variants on known DSD-genes. Testicular biopsy was performed. Fluorescence in situ hybridization (FISH) was used to test whether a sex chromosome mosaicism was present in the oral epithelial cells or gonad tissue of patients with DSD and with XYY in blood. Among 4,437 DSD males who received cytogenetic evaluation, 14 patients with 47,XYY were identified. By contrast, five individuals among the 6,259 controls had 47,XYY. XYY in blood is more frequent among males with DSD than in other males (p = 0.004). The XYY karyotypes were confirmed again by GTG-banding in blood samples and by FISH performed on oral epithelial cells. ES on seven XYY DSD patients was successfully performed, but results did not identify any pathogenic variant on 55 known DSD genes. Gonad biopsy (n = 3) revealed testicular dysplasia and true hermaphroditism. FISH of gonad tissues (n = 3) showed that all of the samples had mosaic for X/XY/XYY. This study is the first to investigate the relationship between XYY in blood and DSD. The knowledge that XYY is in the blood and in oral cells have X/XY/XYY mosaicism in gonadal tissue is new for both researchers and clinicians who seek to understand the genetic basis of DSD males.

Disorder of Sexual Development and Congenital Heart Defect in 47XYY: Clinical Disorder or Coincidence?

Background. 47XYY syndrome is a rare sex chromosome variation characterized by an additional Y chromosome. Most patients with 47XYY karyotype have normal phenotype. This disorder seems associated with a higher risk of developing behavioral and cognitive problems, tall stature, and infertility in adulthood. Sexual development disorder is a rare finding. We report a first case with an abnormal left coronary artery originating from the pulmonary artery in a 47XYY patient. Case. A one-month-old child was referred for ectopic testis and micropenis. Physical examination revealed facial dysmorphia, micropenis, and curvature of the penis with nonpalpable testis. Laboratory tests showed decreased total testosterone and anti-Mullerian hormone (AMH) levels. Blood karyotyping revealed a 47XYY chromosomal formula. At the age of 3 months, the patient developed dyspnea and tachycardia. Echocardiography revealed an anomalous left coronary artery from pulmonary artery with left ventricular dysfunction requiring surgical revascularization by direct reimplantation of the left coronary artery system. Our second case was a 3-year-old child referred for hypospadias with nonpalpable left testicle. Physical examination showed hypertelorism. Blood karyotyping revealed a 47XYY chromosomal formula. Conclusion. To our knowledge, this is the first case of 47XYY syndrome associated with this congenital heart malformation and a sexual development disorder.

No association between Y chromosomal haplogroups and severe acne in the Han Chinese population

Severe acne presents sexual dimorphism in its incidence in Chinese population. It is more prevalent in males. To assess the possible Y chromosomal contribution to severe acne risk in Han Chinese males, we analyzed 2041 Y chromosomal SNPs (Y-SNPs) in 725 severe acne cases and 651 controls retrieved from our recent genome-wide association study data. After data filtering, we assigned 585 cases and 494 controls into 12 Y chromosomal haplogroups based on 307 high-confidence Y-SNPs. No statistically significant difference in the distribution of Y chromosomal haplogroup frequencies was observed between the case and control groups. Our results showed a lack of association between the incidence of severe acne and the different Y chromosomal haplogroup in the Han Chinese population.

47,XYY syndrome: clinical phenotype and timing of ascertainment

OBJECTIVE

To describe auxologic, physical, and behavioral features in a large cohort of males with 47,XYY (XYY), ages newborn to young adult.

STUDY DESIGN

This is a cross-sectional descriptive study of male subjects with XYY who were evaluated at 1 of 2 specialized academic sites. Subjects underwent a history, physical examination, laboratory testing, and cognitive/behavioral evaluation.

RESULTS

In 90 males with XYY (mean age 9.6 ± 5.3 years [range 0.5-36.5]), mean height SD was above average (1.0 ± 1.2 SD). Macrocephaly (head circumference >2 SD) was noted in 28/84 (33%), hypotonia in 57/90 (63%), clinodactyly in 47/90 (52%), and hypertelorism in 53/90 (59%). There was testicular enlargement for age (>2 SD) in 41/82 (50%), but no increase in genital anomalies. No physical phenotypic differences were seen in boys diagnosed prenatally vs postnatally. Testosterone, luteinizing hormone, and follicle stimulating hormone levels were in the normal range in most boys. There was an increased incidence of asthma, seizures, tremor, and autistic spectrum disorder (ASD) compared with the general population rates. Prenatally diagnosed boys scored significantly better on cognitive testing and were less likely to be diagnosed with ASD (P < .01).

CONCLUSIONS

The XYY phenotype commonly includes tall stature, macrocephaly, macroorchidism, hypotonia, hypertelorism, and tremor. Physical phenotypic features were similar in boys diagnosed prenatally vs postnatally. Prenatal diagnosis was associated with higher cognitive function and less likelihood of an ASD diagnosis.

Nonmosaic 47,XYY syndrome presenting with male infertility: case series

In this study, we describe nine patients with 47,XYY presenting with male infertility. All patients were subjected to history taking, clinical examination, duplex ultrasonographic examination of the scrotum, endocrinological investigations and cytogenetic analysis of peripheral lymphocytes. Two patients tried intracytoplasmic sperm injection (ICSI). Our results showed that seven patients were oligospermic and two patients were azoospermic. Bilateral varicocele was detected in seven patients. The hormonal levels in the majority of the patients were within normal range. Two patients showed improvement after varicocelectomy. The wife of one of the oligospermic patients became successfully pregnant after the first trial of ICSI. In conclusion, this report suggests that patients with XYY may present with primary infertility and may show oligospermia and nonobstructive azoospermia. Careful clinical, ultrasonographic, endocrinological and cytogenetic examinations should be a part of their diagnostic work-up for the proper management of these patients. In addition, ICSI may be a hope for some of these patients.

Effects of sex chromosome aneuploidies on brain development: evidence from neuroimaging studies

Variation in the number of sex chromosomes is a relatively common genetic condition, affecting as many as 1/400 individuals. The sex chromosome aneuploidies (SCAs) are associated with characteristic behavioral and cognitive phenotypes, although the degree to which specific individuals are affected can fall within a wide range. Understanding the effects of different dosages of sex chromosome genes on brain development may help to understand the basis for functional differences in affected individuals. It may also be informative regarding how sex chromosomes contribute to typical sexual differentiation. Studies of 47,XXY males make up the bulk of the current literature of neuroimaging studies in individuals with supernumerary sex chromosomes, with a few small studies or case reports of the other SCAs. Findings in 47,XXY males typically include decreased gray and white matter volumes, with most pronounced effects in the frontal and temporal lobes. Functional studies have shown evidence of decreased lateralization. Although the hypogonadism typically found in 47,XXY males may contribute to the decreased brain volume, the observation that 47,XXX females also show decreased brain volume in the presence of normal pubertal maturation suggests a possible direct dosage effect of X chromosome genes. Additional X chromosomes, such as in 49,XXXXY males, are associated with more markedly decreased brain volume and increased incidence of white matter hyperintensities. The limited data regarding effects of having two Y chromosomes (47,XYY) do not find significant differences in brain volume, although there are some reports of increased head size.

Extreme Tall Stature in a Japanese Boy with a 48,XXYY Karyotype

We report an 18-yr-old Japanese boy with a 48,XXYY karyotype and extreme tall stature (194 cm). A GnRH test at 12.5 yr of age showed hypergonadotropism (LH, 4.2 → 72.2 mIU/mL; FSH, 28.9 → 61.7 mIU/mL), and an hCG test at 15.5 yr of age revealed a normal testosterone response (1.67 → 4.08 ng/mL). The tall stature is remarkable, because the mean adult height of Caucasian 48,XXYY patients is 181 cm. Although the underlying factors for the tall stature are unknown, this report indicates an association of the 48,XXYY karyotype with marked tall stature.

Maintaining continuity through a scientific revolution: a rereading of E. B. Wilson and T. H. Morgan on sex determination and Mendelism

A rereading of the American scientific literature on sex determination from 1902 to 1926 leads to a different understanding of the construction of the Mendelian-chromosome theory after 1910. There was significant intellectual continuity, which has not been properly appreciated, underlying this scientific "revolution." After reexamining the relationship between the ideas of key scientists, in particular Edmund B. Wilson and Thomas Hunt Morgan, I argue that, contrary to the historical literature, Wilson and Morgan did not adopt opposing views on Mendelism and sex determination. Rather, each preferred a non-Mendelian explanation of the determination of sex. Around 1910, both integrated the Mendelian and non-Mendelian theories to create a synthetic theory. One problem was the need to avoid an overly deterministic view of sex while also accepting the validity of Mendelism. Morgan's discovery of mutations on the X chromosome takes on different significance when set in the context of the debate about sex determination, and Calvin Bridges's work on sex determination is better seen as a development of Morgan's ideas, rather than a departure from them. Conclusions point to the role of synthesis within fields as a way to advance scientific theories and reflect on the relationship between synthesis and explanatory "pluralism" in biology.

Public concern about genetics

Throughout the twentieth century and continuing into the present, the general public has been fascinated by advances in genetic knowledge. At times, individuals and groups have either inadvertently or deliberately misused genetic knowledge in the service of political goals. At other times, advances in genetics have challenged deeply held societal or religious beliefs. During the 1990s, there were many advances that focused an unprecedented level of public attention and concern on genetics. In particular, the public has expressed deep concern about gene mapping, cloning, and genetically modified foods. In each case, the origin of the concern and the nature of the public response have been different. I consider these topics and argue that the scientific community must increase its commitment to public discourse.

Cladistic association analysis of Y chromosome effects on alcohol dependence and related personality traits

Association between Y chromosome haplotype variation and alcohol dependence and related personality traits was investigated in a large sample of psychiatrically diagnosed Finnish males. Haplotypes were constructed for 359 individuals using alleles at eight loci (seven microsatellite loci and a nucleotide substitution in the DYZ3 alphoid satellite locus). A cladogram linking the 102 observed haplotype configurations was constructed by using parsimony with a single-step mutation model. Then, a series of contingency tables nested according to the cladogram hierarchy were used to test for association between Y haplotype and alcohol dependence. Finally, using only alcohol-dependent subjects, we tested for association between Y haplotype and personality variables postulated to define subtypes of alcoholism-antisocial personality disorder, novelty seeking, harm avoidance, and reward dependence. Significant association with alcohol dependence was observed at three Y haplotype clades, with significance levels of P = 0.002, P = 0.020, and P = 0.010. Within alcohol-dependent subjects, no relationship was revealed between Y haplotype and antisocial personality disorder, novelty seeking, harm avoidance, or reward dependence. These results demonstrate, by using a fully objective association design, that differences among Y chromosomes contribute to variation in vulnerability to alcohol dependence. However, they do not demonstrate an association between Y haplotype and the personality variables thought to underlie the subtypes of alcoholism.

Intelligence and achievement in children with extra X aneuploidy: a longitudinal perspective

Forty-seven children (35 male, 12 female) identified as having a supernumerary X chromosome by neonatal screening were studied psychologically from childhood to late adolescence. This paper compares their findings relative to sibling controls on tests of intelligence and achievement collected over a 14-year period. Children with a supernumerary X chromosome were found to score consistently below controls on Verbal IQ and subtests comprising the Verbal Comprehension factor but they did not differ on Performance IQ, which was in the normal range. At all ages, they showed poorer reading and arithmetic achievement; relative risk for reading and arithmetic impairment was 2.6 and 2.6 in males and 1.1 and 1.7 in females. Males with an extra X chromosome were more likely to receive special education than females, who more often failed a grade. Academic achievement was not affected in aneuploid children with higher levels of intelligence. Overall, these results suggest milder impairment than previously reported, particularly among trisomy X females.

The genetics of mental retardation

Individuals affected by mental retardation are a clinically and aetiologically heterogeneous group. This heterogeneity is particularly highlighted when we consider the genetics of mental retardation. Recent advances in molecular genetic techniques have enabled us to understand more about the molecular basis of several genetic syndromes associated with mental retardation. In contrast, where there is no discrete cause, the interplay of genetic and environmental influences remains poorly understood.

Psychiatric genetics. Misbehaving monoamine oxidase gene

A nonsense mutation in the X-linked monoamine oxidase A gene has been associated with sex-linked aggressive behaviour.

Growth during puberty in the XYY boy

The availability of a cohort of eight unselected XYY boys identified by newborn cytogenetic screening has enabled their growth to be studied longitudinally in comparison with controls from the same population. While no difference had been found in dimensions at birth, increased height velocity in childhood resulted in the XYY boys being 7.6 cm taller at the onset of their pubertal growth spurt. Increased intensity of growth at puberty with a peak height velocity of 10.6 cm/year contributed to their adult height of 188.1 cm. XYY boys showed twice the male-female difference in height implying that genes on the Y chromosome exert a quantitative effect on the sexual dimorphism of growth.

From abuse to violence: psychophysiological consequences of maltreatment

This paper reviews the psychophysiological literature related to violent behaviors. It explores the interactions of environmental influences, pain, stressors, hormones, and neurotransmitters. It presents ways in which maltreatment in the form of abuse or neglect exacerbates preexisting psychobiological vulnerabilities. It proposes that whatever forces increase impulsivity and irritability, engender hypervigilence and paranoia, diminish judgment and verbal competence, and curtail the recognition of pain in the self and others, will enhance violence, and presents evidence that maltreatment has all of these effects.

A review of Klinefelter's syndrome in children and adolescents

Klinefelter's syndrome (XXY syndrome) has been defined as the spectrum of phenotypic features resulting from a sex chromosome complement that includes two or more X chromosomes and one or more Y chromosomes. Cytogenetic surveys conducted across the world have identified a sizable population of XXY males, who have been studied extensively from the newborn period through adolescence. The longitudinal studies of these boys have produced an accurate and reliable account of the growth and development of the XXY male. There now exists a growing body of knowledge that suggests that XXY boys often experience language deficits, neuromaturational lag, academic difficulties, and psychological distress, which may be reduced or ameliorated by early identification, anticipatory guidance, and proper medical management.

Genetic considerations in childhood epilepsy

This report reviews various lines of evidence demonstrating important genetic influences in the epilepsies, with special emphasis on childhood epilepsy. Five pertinent topics are discussed: (a) examples of dominant, recessive, and X-linked single-gene disorders known to be associated with epilepsy, (b) examples of gross chromosomal aberrations associated with epilepsy, (c) discussion of multifactorial and polygenic inheritance and issues of genetic heterogeneity with specific reference to idiopathic generalized epilepsy, febrile seizures, and infantile spasms, (d) brief review of experimental clues to possible pathogenetic mechanisms underlying genetic forms of epilepsy, and (e) an overview of strategies for applying genetic linkage analysis to hereditary epileptic disorders.

Incidence of chromosome abnormalities in newborn children. Comparison between incidences in 1969-1974 and 1980-1982 in the same area

As part of an ongoing study of the influence of environmental factors on pregnancy, childbirth, and fetuses, comparisons have been made between incidences in 1969-1974 and in 1980-1982 of chromosome aberrations in liveborn children in the same area of Denmark. The incidence of chromosome aberrations in the first period was 2.6 per 1000, compared with 41. per 1000 during the latter period. However, the difference was mainly due to an increase in inversions, and this in turn was due to a difference in chromosome staining methods between the two periods. It is concluded that the Danish study and similar studies in the United States, Canada, and Scotland indicate that early detection of chromosome aberrations by chromosome examination at birth is indicated in order to be able to inform and counsel parents of children with chromosome aberrations. Chromosome examination at birth is also of importance in the diagnosis of structural inheritable chromosome aberrations and consequent family investigation and genetic counseling.

A possible association of Y chromosome heterochromatin with stature

A correlation between Y chromosome length and stature was statistically analyzed in a normal male population of 142 Japanese students with a mean age of 24.0 years. Evidence was obtained that increased length of the heterochromatic band Yq12 may be associated with increased height: The correlation coefficient between band Yq12 length and height was 0.17, statistically significant at the 5% level. And, taller males had longer Y chromosomes, in which the mean length of band Yq12 was significantly longer than that of shorter males. No correlation was seen between length of the euchromatic band Yq11 and stature. The present study reveals a possible effect of Yq heterochromatin on the development of body height in man.

The etiology of violent behavior. An overview

Society often considers violent people to be mentally ill, and a significant number of patients exhibit violent behavior. For the assessment of violent individuals, a thorough understanding of the complex biopsychosocial causes of violence is required. This paper critically reviews recent investigations of the multiple causes of violence to clarify those aspects that can be helpful to clinicians in their inquiries.

Sex chromosome disorders

A critical and comprehensive review of the major sex chromosome disorders. The introduction briefly outlines the cytogenetic background to these disorders and refers to earlier reviews. The paper then reviews the clinical and psychiatric aspects of the various chromosome disorders. Male and female phenotypes are dealt with separately, with emphasis on psychological and behavioural manifestations including antisocial behaviour. Medico-legal implications are also reviewed, as are the implications for research.

Abnormal cerebral cortical convolutions in an XYY fetus

Because of maternal disease a pregnancy was electively terminated at 21 weeks of fetal gestation. At autopsy the fetus showed an abnormal pattern of cerebral cortical convolutions involving the frontal lobes. Karyotpic analysis revealed an XYY sec chromosome constitution. This observation, if confirmed in other XYY cases, raises the possibility that a developmental abnormality of the cerebral cortex may be involved in the higher-than-normal risk for behavioral disability exhibited by men with this genotype.

Frequency of XYY males in Wisconsin state correctional institutions

Karotyping of 3011 males at five Wisconsin state correctional institutions revealed that 1% had a chromosome abnormality. The frequency of occurrence of the XYY complement was about 5 times that for newborn males. Approximately the same rate was found among 2556 males in the three penal institutions for adults. The frequency of XYY at the institution for juvenile offenders was about ten times background. The relatively low frequency of XYY (0.38%) found at the mental-penal institution may have been due to previous sampling done there. Of the 16 XYY males discovered, only two were below the 85th percentile for height. A relatively low frequency of XYY was found among black males. Our data contradict the notion that a high rate of XYY among adult males in penal settings may be due to a disproportionately large number of tall men in prisons.

An XYY man

This case report describes a young man with a 47, XYY karyotype who was convicted of arson. He suffered from a cardiac disorder which may well have been part of the XYY syndrome rather than a chance association. His abnormal karyotype was disclosed in court and used by the defence in a plea in mitigation.

Follow-up of 11 XYY males with impulsive and/or sex-offending behaviour

Eleven behaviourally abnormal XYY males who had been treated in a structured combined programme of antiandrogen medication and counseling were followed up 1 year after cessation of the programme. Behavioural ratings were made in each of 5 categories: assault against people, destructiveness against things, threatening behaviour, stealing, and self-harming. On examining the follow-up findings, therapeutic success appeared questionable.

Chromosomes and the gynecologist

Recent advances in cytogenetic techniques made a valuable contribution toward the modern practice of obstetrics and gynecology. The state of the art regarding the application of these techniques is reviewed in the following areas: the clinical features related to the various sex and autosomal chromosomal anomalies, the cytogenetics of gynecologic malignancies, the chromosomal analysis of spontaneous abortion and of parents with habitual abortions. Chromosome studies in male infertility revealed abnormalities in 11.5 per cent of 69 patients with azoospermia and 9.1 per cent of 165 patients with oligospermia. Among 77 patients with primary amenorrhea, 27.3 per cent revealed chromosomal abnormalities compared to 3.8 per cent in 103 patients with secondary amenorrhea. The term "ovotesticular dysgenesis" is used for the first time in the literature to describe a specific histologic type of streak gonad which contains ovarian stroma and dysgenetic testicular tubules.

Two new cases of XYY chromosome complement: and a review of the literature

Two cases with XYY chromosome complement are presented and compared with 153 cases described in the literature. Some patients with abnormalities of personality development and manifest psychopathology may have sex chromosome abnormalities and should be studied further for the interaction of genetic and environmental factors in personality development. In particular, tall, schizoid impulsive men with a history of criminality, arson or sexual offences should be screened for this particular genetic configuration. Because of the biased manner by which most of the cases are found, it is not yet known whether an XYY genotype results in a characteristic phenotype. What is needed is a genetic study of a normal population and a prospective study of newborns with various genotypes which would, unfortunately, create complex research and ethical problems.

XYY males. Some clinical and psychiatric aspects deriving from a survey of 1,811 males in hospitals for the mentally handicapped

A survey of 1,811 mentally handicapped males in eighteen hospitals is described. Males discovered with supernumerary Y chromosomes numbered 15, of whom 12 were 47,XYY. Some of the physical, social, psychological and psychiatric findings are described and compared with groups matched for IQ and height. The main psychiatric findings are diminished intelligence, retardation in development of secondary sexual characteristics, and poor emotional control leading to inadequate social adaptive patters which are described and discussed.

No evidence for a correlation between behaviour and the size of the Y chromosome

Y chromosome variation has been studied in three groups of Norwegian males: 35 boys from an adolescent psychiatric hospital; 45 men from a hospital for hard-to-manage or dangerous, psychotic men; and 26 boys from two ordinary school classes. Y chromosomes with 1, 2, and 3 brightly fluorescing bands were found in all three groups. One boy carried a Y with no bands. The mean values of the Yf/Yq ratio were not significantly different in the three groups (Yf is the length of the distal, brightly fluorescing part of Yq). Two cases of XY/XYY mosaicism were found among the psychotic men. The study shows that the human species is polymorphic with regard to the size of the Y chromosome, i.e. the number of fluorescent bands in the long arm. No phenotypical manifestation of this polymorphism, particularly as regards behaviour, was found.

Height and seriousness of crime in XYY men

The case histories of XYY males in two security settings were ranked by degree of seriousness of crime. The correlations of these scores with height were either zero (for data of Daly with the history of the propositus excluded) or positive (for data of Jacobs et al., P less than 0.05). For both studies, the results were contrary to the expectation of negative correlation which would be found if, in accord with Hunter's suggestion, authorities were biased to place XYYs in security settings because of the more threatening appearance associated with larger stature.