The mental implications of sex chromosome aberrations

Klinefelter's syndrome (XXY) as a genetic model for psychotic disorders

Males with an extra-X chromosome (Klinefelter's syndrome) frequently, although not always, have an increased prevalence of psychiatric disturbances that range from attention deficit disorder in childhood to schizophrenia or severe affective disorders during adulthood. In addition, they frequently have characteristic verbal deficits. Thus, examining brain magnetic resonance imaging (MRI) scans of these individuals may yield clues to the influence of X chromosome genes on brain structural variation corresponding to psychiatric and cognitive disorders. Eleven adult XXY and 11 age matched XY male controls were examined with a structured psychiatric interview, battery of cognitive tests, and an MRI scan. Ten of eleven of the XXY men had some form of psychiatric disturbance, four of whom had auditory hallucinations compared with none of the XY controls. Significantly smaller frontal lobe, temporal lobe, and superior temporal gyrus (STG) cortical volumes were observed bilaterally in the XXY men. In addition, diffusion tensor imaging (DTI) of white matter integrity resulted in four regions of reduced fractional anisotropy (FA) in XXY men compared with controls, three in the left hemisphere, and one on the right. These correspond to the left posterior limb of the internal capsule, bilateral anterior cingulate, and left arcuate bundle. Specific cognitive deficits in executive functioning attributable to frontal lobe integrity and verbal comprehension were noted. Thus, excess expression of one or more X chromosome genes influences both gray and white matter development in frontal and temporal lobes, as well as white matter tracts leading to them, and may in this way contribute to the executive and language deficits observed in these adults. Future prospective studies are needed to determine which gene or genes are involved and whether their expression could be modified with appropriate treatments early in life. Brain expressed genes that are known to escape inactivation on extra-X chromosomes would be prime candidates.

Neurobiology of emotion and high risk for schizophrenia: role of the amygdala and the X-chromosome

Abnormalities in emotion processing and in structure of the amygdala have consistently been documented in schizophrenia. A major question is whether amygdala abnormalities reflect a genetic vulnerability for the disease. In the present paper, we reviewed Magnetic Resonance Imaging (MRI) studies that reported amygdala measures in several high-risk populations: subjects from the general population with subclinical schizophrenia symptoms and relatives of schizophrenia patients. In addition, we reviewed the evidence regarding Klinefelter syndrome (characterised by an additional X-chromosome), which has also been related to an increased risk for schizophrenia. Overall, the evidence points to structural abnormalities of the amygdala in individuals at increased risk for schizophrenia. Although the genetic basis of amygdala deficits remains unclear, abnormalities (of genes) on the X-chromosome might play a role as suggested by the evidence from individuals with sex chromosome aneuploidies. We propose that amygdala abnormalities are an endophenotype in schizophrenia and may account for subtle emotional processing deficits that have been described in these high-risk groups.

Klinefelter's syndrome

Klinefelter's syndrome is the most common genetic cause of human male infertility, but many cases remain undiagnosed because of substantial variation in clinical presentation and insufficient professional awareness of the syndrome itself. Early recognition and hormonal treatment of the disorder can substantially improve quality of life and prevent serious consequences. Testosterone replacement corrects symptoms of androgen deficiency but has no positive effect on infertility. However, nowadays patients with Klinefelter's syndrome, including the non-mosaic type, need no longer be considered irrevocably infertile, because intracytoplasmic sperm injection offers an opportunity for procreation even when there are no spermatozoa in the ejaculate. In a substantial number of azoospermic patients, spermatozoa can be extracted from testicular biopsy samples, and pregnancies and livebirths have been achieved. The frequency of sex chromosomal hyperploidy and autosomal aneuploidies is higher in spermatozoa from patients with Klinefelter's syndrome than in those from normal men. Thus, chromosomal errors might in some cases be transmitted to the offspring of men with this syndrome. The genetic implications of the fertilisation procedures, including pretransfer or prenatal genetic assessment, must be explained to patients and their partners.

Klinefelter syndroom en psychiatrische stoornissen: Twee gevalsbeschrijvingen en een literatuuroverzicht

Klinefelter syndrome is a genetically determined disorder characterized by an additional X-chromosome. Apart from the phenotypical features, the literature about this disorder mentiones a psychopathological phenotype comprising mainly psychoses, depressive diseases and personality disorders. A substantial number of patients presents with mild to moderate mental retardation. In this paper, two case reports are described and their psychopathology is compared with the data from the existing literature.

Relevance of sequential development of dermatoglyphics to schizophrenia

Since the embryogeneses of epidermal ridges of hands and feet are reported to be identical, although those of the feet develop two or three weeks later, a tendency for symmetry or correspondence between each side finger and toe pairs could be envisaged. Any prenatal insult could disturb such developmental mechanisms, causing the lowering of either finger or toe ridge counts which might result in augmentation of differences between them. To test this hypothesis, the differences between each side thumb and big toe ridge counts of 89 schizophrenic patients and 65 control subjects were assessed. These samples were also subgrouped into those with and without identical pattern distributions on each side of their thumb and big toe pairs. Female schizophrenics who displayed identical patterns manifested significantly greater differences between their right thumb and big toe ridge counts in comparison to the control subjects (P = 0.0142). To elucidate the contributory digit for such a greater difference, the ridge counts of the right thumbs and big toes of the female patients were compared with the corresponding counts of the control subjects. The mean ridge count of the big toes was lesser in the patient group compared with that in the control subjects, a difference, however, that did not attain statistical significance.

An examination of linkage of schizophrenia and schizoaffective disorder to the pseudoautosomal region (Xp22.3)

We investigated linkage between schizophrenia and the loci DXYS14, DXYS17, and MIC2 within the pseudoautosomal region in 85 families with two or more siblings suffering from schizophrenia or schizoaffective disorder. A maximum lod score of 2.44 was reached at MIC2, with a dominant model of inheritance at a recombination fraction of 0.367 in females and 0.046 in males (a F:M sex ratio > 1, i.e. opposite to that expected with a pseudoautosomal locus). Evidence consistent with linkage (P = 0.01) was also obtained with a sibling pair analysis at the MIC2 locus. These data do not support (although they do not definitively exclude) a locus within the pseudoautosomal region; they are consistent with the presence of a gene that predisposes to schizophrenia in the sex-specific regions of the X and Y chromosomes.

MRI and SPECT of Klinefelter's syndrome with various neuropsychiatric symptoms: a case report

We present here magnetic resonance imaging (MRI) and single photon emission computed tomography with 123I-N-isopropyl-p-iodoamphetamine (123I-IMP-SPECT) of a patient suffering from Klinefelter's syndrome with various neuropsychiatric symptoms. He was a 30-year-old male, who showed impaired consciousness seizures, auditory hallucination, delusion of reference, delusion of grandeur, psychomotor excitement and intellectual impairment. Although no focal lesion was detected by computed tomography or T1-weighted MRI, T2-weighted MRI provided a heterogeneous high-signal-intensity lesion of the inferior part of the left temporal lobe, which was not enhanced with Gd-DTPA. In addition 123I-IMP-SPECT exhibited focal hypoperfusion in the left temporal lobe on the early images. We suggest that the neuropsychiatric symptoms of this case are associated with the focal organic brain dysfunction which was revealed by MRI and 123I-IMP-SPECT.

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.

Klinefelter syndrome: the need for early identification and treatment

A 14-year-old boy presented with severe academic difficulties, emotional disturbance, borderline mental retardation, tall stature, delayed sexual development, small testes, and gynecomastia. Chromosomal analysis revealed an additional X chromosome compatible with the diagnosis of 47, XXY Klinefelter Syndrome. This case retrospectively follows the progression of learning and behavioral problems occurring in the primary grades prior to the diagnosis of Klinefelter Syndrome and reports the effects of psychiatric treatment, modified educational placement, testosterone supplementation, and corrective surgery in adolescence. The early identification of Klinefelter Syndrome is vital to the XXY male in that many of the developmental, behavioral and emotional problems associated with an additional X chromosome are amenable to treatment.

The continuum of psychosis and its genetic origins. The sixty-fifth Maudsley lecture

Attempts to draw a line of genetic demarcation between schizophrenic and affective illnesses have failed. It must be assumed that these diseases are genetically related. A postmortem study has demonstrated that enlargement of the temporal horn of the lateral ventricle in schizophrenia but not in Alzheimer-type dementia is selective to the left side of the brain. This suggest that the gene for psychosis is the 'cerebral dominance gene', the factor that determines the asymmetrical development of the human brain. That the psychosis gene is located in the pseudoautosomal region of the sex chromosomes is consistent with observations that sibling pairs with schizophrenia are more often than would be expected of the same sex and share alleles of a polymorphic marker at the short-arm telomeres of the X and Y chromosomes above chance expectation. That the cerebral dominance gene also is pseudoautosomal is suggested by the pattern of verbal and performance deficits associated with sex-chromosome aneuploidies. The psychoses may thus represent aberrations of a late evolutionary development underlying the recent and rapid increase in brain weight in the transition from Australopithecus through Homo habilis and Homo erectus to Homo sapiens.

Chronic psychosis in Turner's syndrome. Case report and a review

A 59-year-old woman with Turner's syndrome developed epilepsy, diabetes mellitus, chronic psychosis, and subsequently pre-senile dementia. This would endorse the view that psychosis in Turner's syndrome arises through brain damage.

Testosterone treatment of an XXYY male presenting with aggression: a case report

A hypogonadal male with 48 XXYY Karyotype--a rare Klinefelter's syndrome variant--is presented with review of the literature. Cautious initiation of testosterone replacement therapy to our patient was associated with sexual maturation and, interestingly enough, disappearance of his longstanding aggressive fantasies and behaviors towards females. An explanatory hypothesis is proposed and clues for early detection of the syndrome are suggested.

Cytogenetic studies of males with schizophrenia. Screening for the fragile X chromosome and other chromosomal abnormalities

Genetic factors appear to play a role in the etiology of schizophrenia, although no specific genetic mechanism has yet been identified. As a preliminary measure in the search for the chromosomal location of a gene or genes relevant to this illness, cytogenetic screening of populations of patients might provide clues for further in depth molecular studies. Additionally, since the X chromosome has been implicated as a possible site, specific examinations aimed at identifying abnormalities in this chromosome including the presence of the fragile X site, could also be important. The following report reviews the previous literature on chromosomal aberrations in schizophrenia and presents data from a new survey of 46 unrelated male patients with schizophrenia. No chromosomal aberrations or folate-sensitive fragile sites were found in samples from these patients.

Mental illness and sex chromosome aberration: renewed interest in light of a current survey

Chromosome determination in 134 men with psychotic disorder revealed sex chromosome aberrations in three patients; one with karyotype 47, XXY, one with 47, XXY/46, XY, and one with 46, XY/45, XO. The frequency of sex chromosome changes in our population (2%) was significantly increased compared to that in newborns. Since sex chromosome aberrations may play an important role in the etiology of psychiatric disorders, chromosome determination should be included among the routine investigations of patients with psychotic symptoms.

Genetic disorders presenting as "schizophrenia". Karl Bonhoeffer's early view of the psychoses in the light of medical genetics

There is overwhelming empirical evidence for the influence of genetic factors in the etiology of schizophrenic psychoses. An appreciable and still increasing number of exogenous factors have been known for decades that are capable of inducing psychoses that present as "schizophrenia" or are more or less similar to it. In this article, genetic disorders--chromosomal abnormalities and Mendelian diseases--are summarized that may be associated with such psychoses. These disorders frequently but not necessarily exhibit additional physical symptoms. Although the majority of schizophrenic psychoses can so far not be explained by exogenous factors or well-defined genetic disorders, the proportion of these etiologies among all cases may be higher than presumed so far, because they evade detection. Data from the literature are discussed in the light of Karl Bonhoeffer's early concept of exogenous reaction types and modern medical genetics.

Yq deletion with short stature, abnormal male development, and schizoid character disorder

A 33-year-old male with short stature, abnormal male sexual differentiation, aspermia, and schizoid character disorder is described, who had a Y chromosome with a deleted long arm. The correlation of the symptoms, including the psychotic abnormality, with the cytogenetic finding is discussed.

Schizophrenia and Klinefelter's syndrome

Psychiatric disorder in relation to Klinefelter's syndrome is reviewed. A well documented case report is presented of a schizophreniform illness in a patient with Klinefelter's.

Klinefelter's syndrome and schizophrenia

The prevalence of Klinefelter's Syndrome in new-born males in large surveys throughout the world has shown a scatter of 1.4 to 1.9 per thousand. Forssman (1970) accepted by pooling results a figure of 0.17 per cent as the average proportion of males born with at least one too many X chromosomes in some or all cell lines. Studies of mental hospital populations have consistently shown a higher prevalence of extra X chromosomes in males, averaging 0.54 per cent. The two largest studies, in Great Britain (Maclean et al, 1968) and in Sweden (Hambert, 1966) made no differentiation in the psychiatric diagnosis of the patients, although Hambert stated that the high prevalence did not stem from the mentally retarded population.

Psychiatric examination of all eight adult males with the karyotype 46,XX diagnosed in Denmark till 1976

Psychiatric examination has been made in all eight adult males with the karyotype 46,XX diagnosed in Denmark til 1976. Apart from emotional immaturity in most probands, no psychopathological traits were found, except in one who had neurotic symptoms. They were all of normal intelligence and socially well adjusted. All had male psychosexual orientation, but weak sexual libido and potency were found in the oldest probands. In several respects males with 46,XX differ from Klinefelter males with the karyotype 47,XXY, and the reasons for this are discussed.

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.

Twenty psychotic males with Klinefelter's syndrome

Twenty males with Klinefelter's syndrome discharged from psychiatric hospitals with diagnoses classified as psychosis are presented. It is concluded that the higher frequency of psychoses in males with the Klinefelter syndrome most probably is due to reactive psychosis. Personality traits commonly found in these males may explain this. The importance of early diagnosis of the Klinefelter syndrome is stressed, as it is believed that treatment and advice in due time may prevent most of the reactive psychoses.

Psychosis in Mental Handicap. The tenth Blake Marsh lecture delivered before the Royal College of Psychiatrists, February 2, 1976

The literature on the purely psychiatric aspects of mental handicap is remarkably limited. In the third edition of Mayer-Gross, Slater and Roth's Clinical Psychiatry, apart from one or two brief incidental mentions elsewhere in the text, the main references consist of just one paragraph on psychoses and two short paragraphs on neuroses included in the section on ‘The Association of Mental Subnormality with Other Syndromes’! Similarly the only reference to mental illness in mental handicap in the eighth edition of Henderson and Gillespie's Text-Book of Psychiatry was a mere four lines on psychosis; by the ninth edition, this had grown to seven lines covering both neuroses and psychoses, but with two of those lines devoted to an admission by the authors of their own lack of knowledge.

[Sex chromosome aberration screening among male psychiatric patients (author's transl)]

The authors report of sex chromosome aberration screenings among the patients of the male psychiatric department, University Medical School, Pecs. 310 patients were investigated. The X-chromatin was detected in buccal smears with thionin-staining and the Y-chromatin in peripheric blood smears with quinacrin-staining by the help of fluorescentoptical technique. Two Klinefelter-patients and one YY-patient were diagnostized. The Klinefelter-patients were psychopaths and mentally subnormal, the YY-patient was a paranoid schizophrenic. The incidence of Klinefelter syndrome is 0.64%, that of the YY syndrome is 0.32%. Mental relations of sex chromosome aberrations are discussed in detail.

Sex chromatin anomaly among Chinese psychiatric inpatients compared to schoolchildren

In a study of sex chromatin abnormality among Chinese psychiatric inpatients, buccal smears were examined from a total of 1,253 psychiatric inpatients (639 males and 614 females). One male psychiatric inpatient (1.6/1000) was chromatin positive (plus ve); two female psychiatric inpatients (3.3/1000) were found to have two sex chromatin bodies (less than e). The lower rate for male inpatients in comparison to Chinese schoolboys (i.3/1000) is thought to reflect a higher rate of mental subnormality in the primary schoolchildren. This is considered attributable to the special nature of the school system and psychiatric patient facilities in Taiwan. The higher rate for female inpatients in comparison with the schoolgirls (0.5/1000) tends to indicate a predisposition to mental disorder in favor of psychosis associated with double sex chromatin abnormality in the female.

XYY karyotype in a pair of monozygotic twins: a 17-year life-history study

We have recently had the opportunity to investigate clinical and behavioural characteristics of a pair of 17-year-old twin boys who were discovered to have the XYY karyotype (18). Since these twins, known to this department since infancy, had been studied at the age of three, early direct findings as well as retrospective data are available regarding their symptoms and development.

Prisoners of XYY constitution: psychological aspects

There is little definite information about the psychological correlates of the XYY chromosome anomaly. Hope et al. (1967) made observations on 7 subjects relevant to Reactive-Narcissism (Ss scores lower), Dependence (higher), Over-activity (lower), HOQ (More obsessional). Other studies with inconclusive results have been made by Little (1968), Nielsen and Tsuboi (1969) 9SS, Street and Watson (1969) 22SS, and Forssman (1970) 11Ss.