Behavioral phenotypes of genetic syndromes: a reference guide for psychiatrists

OBJECTIVE

To review the literature on behavioral phenotypes of genetic syndromes, displaying the data as a reference guide for everyday practice.

METHOD

A computerized search was performed for articles published in the past 10 years, and selected papers were surveyed.

RESULTS

The behavioral phenotypes of 11 major genetic syndromes were reviewed including the following topics: genetic etiology, genetic counseling, physical features, medical problems, cognitive and behavioral profile, and psychopathology. The speculated correlation between the identified gene and the pathophysiology of the cognitive and behavioral features is discussed.

CONCLUSIONS

Updated knowledge of behavioral phenotypes will help psychiatrists identify these conditions, refer the patient and his/her family for genetic diagnosis and counseling, make specific treatment recommendations, and contribute to research and syndrome delineation.

Genetic studies of bipolar affective disorder in large families

BACKGROUND

Genetic factors are known to be important in the aetiology of bipolar disorder.

AIMS

To review linkage studies in extended families multiply affected with bipolar disorder.

METHOD

Selective review of linkage studies of bipolar disorder emphasising the gains and drawbacks of studying large multiply-affected families and comparing the statistical methods used for data analysis.

RESULTS

Linkage of bipolar disorder to several chromosome regions including 4p, 4q, 10p, 12q, 16p, 18q, 21q and Xq has first been reported in extended families. In other families chromosomal rearrangements associated with affective illnesses provide signposts to the location of disease-related genes. Statistical analyses using variance component methods can be applied to extended families, require no prior knowledge of the disease inheritance, and can test multilocus models.

CONCLUSION

Studying single large pedigrees combined with variance component analysis is an efficient and effective strategy likely to lead to further insights into the genetic basis of bipolar disorders.

Life adaptation in 35 adults with sex chromosome abnormalities

PURPOSE

This report from the last phase of the 36-year Denver Study provides information about the adult life adaptation of 35 men and women with sex chromosome abnormalities (SCA) followed since their identification at birth.

METHODS

Sex chromatin screening of 40,000 consecutive newborns between 1964 and 1974 resulted in the cohort of 35 SCA men and women followed to date since birth. Sixteen chromosomally normal siblings served as controls. Data constituting this report was obtained from formal and informal interviews and psychological testing conducted in the final year of this study.

RESULTS

The nonmosaic SCA propositi had lower mean intelligence quotients and psychosocial adjustment scores than did siblings. Consistent with these results, propositi also had lower levels of educational achievement and career success, although most have completed school, married, hold full-time employment, and are financially independent.

CONCLUSIONS

While the SCA adults demonstrated lower levels of cognitive and psychosocial competence, their overall adaptation has been positive, particularly given an early literature suggesting a high rate of psychopathology and severe dysfunction.

[Genetic diseases:recent scientific findings and health and ethical problems]

Genetic diseases are very numerous, even though rare as single conditions: therefore, overall they represent a significant portion of morbidity at population level. The improvement of molecular genetic techniques has brought a great increase in the diagnostic potential toward genetic diseases, concerning either symptomatic or pre-symptomatic individuals and healthy carriers. However, this has frequently unforeseen consequences, such as a discrepancy between diagnostic and therapeutic potentials. Moreover, the development of genetic tests has raised a number of questions regarding ethical, legal e social problems. The Italian guidelines for genetic tests (available on the Internet site of Istituto Superiore di Sanità: http:@www.iss.it) have been elaborated in 1998 to define general principles for performing and managing genetic tests as well as for programming and promoting genetic testing within the public health system. In accordance with recommendations by international bodies (WHO, EU), the Guidelines give emphasis to the appropriate use of both safe and efficacious tests, the performance in laboratories with high quality standards. A further crucial point is the relationship between the health system and individuals: authonomy of decision, psychological and social assistance, as well as adequate attention to ethical and privacy problems should be guaranteed.

Chromosomes in autism and related pervasive developmental disorders: a cytogenetic study

Few studies have examined the occurrence of chromosome abnormalities in a large sample of patients with autism and related pervasive developmental disorders (PDDs). In the present report, the authors examined a consecutive series of 92 children with PDDs (DSM-III-R; 75 males and 17 females). A cytogenetic examination, including growth in folate deficient medium, was performed in all cases. Three patients (3.2%) (two females and one male) showed chromosome abnormalities: deletion of the long arm of chromosome 8; tetrasomy of chromosome 15; and XYY syndrome. Only the subject who had tetrasomy 15 met the criteria for autistic disorder, while the other were diagnosed as suffering from a PDD not otherwise specified (PDDNOS). Another patient showed an abnormal fragile site at Xq27 in three out of 100 cells. However, subsequent molecular studies did not confirm the presence of fragile-X syndrome. These results suggest that chromosome abnormalities are uncommon in traditional autism and may be relatively more common in people with PDDNOS.

Schizophrenia with karyotype mosaic 47,XXY/48,XXY + 8

A case of severe schizophrenia is described in a patient with chromosomal mosaicism of Klinefelter's syndrome (XXY) and trisomy 8. The literature of both syndromes is reviewed and the aetiological implications discussed.

The awareness of chromosomal disarrangements in the evaluation of child psychiatry patients

This case report reviews genetics consultations on psychiatrically hospitalized school-age children. Six of 100 patients were noted to have positive genetic findings: four with congenital anomalies and/or biochemical/metabolic abnormalities and two with chromosomal abnormalities. Three of these patients are used to illustrate the occurrence of genetic abnormalities in psychiatrically hospitalized children. The indications for chromosomal analysis are discussed.

[Partial deletion of the short arm of chromosome 4 (the Wolf-Hirschhorn syndrome) with reference to the neurological and electroencephalographic aspects]

We describe a case of Wolf-Hirschhorn syndrome (partial deletion of the short arm of chromosome 4). The syndrome is characterized by mental and growth retardation and characteristic facial dysmorphism. The fetus was karyotyped for severe intrauterine growth retardation diagnosed on routine ultrasound. High resolution chromosomal analysis of infant and parents showed "de novo" deletion. Very interesting in our case are ictal phenomena and neurological development.

Head circumference and IQ of children with sex chromosome abnormalities

At all ages XXX girls had significantly smaller head circumferences than control girls. Their IQ deficit was 24 points and IQ at age seven correlated significantly with head circumference at birth. In XXY boys, head circumference was significantly reduced at birth and up to nine years of age. The XXY boys' IQ deficit was 22 points, but IQ did not correlate with head circumference, as reductions in the two parameters did not always occur in tandem. The ratio of height-to-head circumference differed most in this group and could be useful in clinical recognition of this condition. XYY boys' head size did not differ from controls, despite their greater height, lower IQ scores indicating an adverse effect of an additional Y chromosome on brain development. The major factor affecting IQ outcome in the cohort was abnormal karyotype, with smaller effects from social class and head growth.

Natural history of trisomy 18 and trisomy 13: II. Psychomotor development

Developmental data were abstracted from medical records on 50 trisomy 18 individuals ranging in age from 1 to 232 months and 12 trisomy 13 individuals ranging in age from 1 to 130 months. Data on the age when trisomy 18 and trisomy 13 children achieved developmental skills were collected from a larger group of 62 trisomy 18 individuals and 14 trisomy 13 individuals whose families filled out parent questionnaires. Developmental quotient (DQ), defined as developmental age divided by chronological age, averaged 0.18 for trisomy 18 and 0.25 for trisomy 13. There was a dramatic drop in DQ from infancy to later childhood. The highest DQs and the greatest variation in DQs were in the first 2-3 years of life. Developmental ages in 7 skill areas were significantly different, with daily living and receptive language having the highest values and motor and communication skills having the lowest. When chronological age was taken into account, there was no significant difference in DQs in the same 7 skill areas, although there was a trend that was similar to the pattern of differences with developmental age. Older children could use a walker, understand words and phrases, use a few words and/or signs, crawl, follow simple commands, recognize and interact with others, and play independently. Walking and some toileting skills were also reported for trisomy 13. Although individuals with trisomy 18 and trisomy 13 were clearly functioning in the severe to profound developmentally handicapped range, they did achieve some psychomotor maturation and always continued to learn.

Counselling following diagnosis of fetal abnormality: a comparison between German, Portuguese and UK geneticists

The principle of non-directiveness in genetic counselling is embraced by all relevant professional bodies. Little is known about the extent to which it is endorsed by geneticists, or incorporated into their clinical practice. The aim of the current study is to document how geneticists in three European countries, Germany, Portugal and the UK, report counselling women at risk for having children with a range of conditions. While geneticists in all three countries reported counselling in a largely non-directive style, this varied both across genetic conditions and between countries. German and Portuguese geneticists were significantly more directive than UK geneticists, although they differed in the way in which they were directive. German geneticists were more likely to encourage continuation of pregnancies, while Portuguese geneticists were more likely to encourage termination of affected pregnancies. There was no strong consensus on approaches to counselling for any of the genetic conditions, defined as agreement between 70% of all three groups of geneticists. Despite strong professional codes of non-directiveness, geneticists report being somewhat directive in some counselling situations. Future research needs to focus on what geneticists are trying to achieve in genetic counselling, how they actually counsel, and with what effects.

The psychiatric, psychological and behavioural functioning of a boy with terminal deletion of the long arm of chromosome 10

The developmental and behavioural functioning of a six-year-old boy with deletion of the long arm of chromosome 10 was evaluated using reliable, standardised, psychological inventories. The information obtained clarified his complex pattern of strengths and needs; it also contributes scientifically derived data to the literature on behavioural correlates of this condition.

A complex chromosome rearrangement in a boy with autism

Autism is a rare behavioral phenotype defined by a qualitative impairment in reciprocal social interaction, impairment in communication and imaginative activity, and a markedly restricted repertoire of activities and interests. It is the most severe and prototypical form of the general category of Pervasive Developmental Disorders of Childhood. Using even strict diagnostic criteria, the currently described etiologies of autism are heterogeneous, with the majority of cases continuing to be idiopathic. At present, it is not clear whether autism is merely a behaviorally defined phenotype arising from diverse etiologies or a separate category of psychological dysfunction for which some unifying etiology exists. Complex chromosome rearrangements (CCR) are rare structural abnormalities involving at least three chromosomes and three or more break-points. We report a 6.5-year-old boy with classic infantile autism and a CCR involving chromosomes 1, 7, and 21. We discuss the possible relationship of his chromosome abnormality to the etiology of his autism.

Trisomy 18 mosaicism with complete peripheral lymphocyte trisomy and normal intelligence

We report a patient with trisomy 18 in all peripheral lymphocytes, mosaicism in cultured fibroblasts, mild nonspecific dysmorphic features, and normal intelligence. Trisomy 18 mosaicism with complete peripheral lymphocytic trisomy has not been previously described. The karyotype of lymphocytes is not diagnostic in the absence of congruent morphologic features.

A family with multiple instances of definite, probable and possible early-onset Alzheimer's disease

A family with a multigenerational history of proven or suspected early-onset Alzheimer's disease (AD) consistent with autosomal-dominant inheritance is described. To date, the pedigree comprises five generations in which there are 13 known affected individuals. The mean age of onset of cognitive deficits in those for whom data are available (n = 11) is 47.6 (s.d. 3.0) years and the mean age of death (n = 10) is 58.8 (s.d. 4.0) years. The variability in the extent and quality of available data illustrates the diagnostic difficulties encountered in ascertaining such an extended pedigree, and the need for caution in interpreting the evidence.

Intellectual functions and personality in subjects with noncongenital myotonic muscular dystrophy

Mental retardation and personality disorders are commonly described among the symptoms of myotonic dystrophy. Nevertheless, this tendency is not supported by systematic studies performed on large samples, whose results are controversial. We studied the cognitive functions and personalities of a group of 28 patients, in whom myotonic dystrophy had commenced in juvenile or adult life. The severity of the disease was variable, but all subjects were self-sufficient. Only 7.1% of subjects showed low intelligence with deterioration of perceptual-motor functions. This was not correlated with the severity of their disease. Women had a substantially lower mean Wechsler-Bellevue score than men. The personality function study of the entire group showed no change of psychiatric relevance but did present a depressive attitude with marked somatic concern and difficulties in establishing relationships in social life.

Chromosomes in anorexia nervosa. A study of 47 cases including a population-based group: a research note

Forty-seven cases with anorexia nervosa (including a total population group) and 47 sex-, age-, and school-matched comparison cases were subjected to chromosome analyses in a blind fashion. No major abnormalities were found in any of the cases. Sex chromatin was analysed in buccal smears from the girls. No differences between the anorexia nervosa and the comparison cases were found. It seems that chromosomal/sex chromatin analyses in anorexia nervosa are not warranted.

Evidence for a pseudo-autosomal locus for schizophrenia using the method of affected sibling pairs

A susceptibility locus for schizophrenia in the 'pseudo-autosomal' region has been proposed on the basis of the reported excess of sex-chromosome aneuploidies (e.g. XXY and XXX) among patients with schizophrenia and the finding that schizophrenic sib-pairs are more often of the same than of the opposite sex. This hypothesis has been tested in 83 sibships with two or more siblings fulfilling Research Diagnostic Criteria for schizophrenia or schizoaffective disorder. Alleles at the pseudo-autosomal telomeric locus DXYS14, which is unlinked with sex, were analysed using the method of affected sib-pairs. Affected sibs shared alleles at DXYS14 more frequently than expected by random Mendelian assortment, supporting genetic linkage between DXYS14 and schizophrenia.

No evidence for a susceptibility locus predisposing to manic depression in the region of the dopamine (D2) receptor gene

Recent reports of cytogenetic abnormalities linked to psychiatric illness and the localisations of the genes for the dopamine (D2) receptor and tyrosinase on the long arm of chromosome 11 have suggested that susceptibility loci for schizophrenia and manic depression might be situated in this region. We could find no evidence for linkage in five Icelandic pedigrees between manic depression and markers in this region, and we have excluded candidate genes coding for the D2 receptor and tyrosinase. We conclude that mutations at loci in this region are not a common cause of manic depression in the population studied.

Autistic features in Joubert syndrome: a genetic disorder with agenesis of the cerebellar vermis

Recent reports in the literature have suggested a link between abnormalities of the cerebellar vermis and the behavioral syndrome of autism. Joubert syndrome is an autosomal recessive disorder characterized by partial or complete agenesis of the cerebellar vermis. However, there is little behavioral or psychiatric description of patients with this genetic condition. In this report, the neuropsychiatric characteristics of two children with Joubert syndrome are described in detail. One child met DSM-III-R diagnostic criteria for autistic disorder, while the other displayed autistic features. The female child displayed stereotypic behavior and impairments in social interaction and communication, had a markedly restricted repertoire of interests, and showed distress over changes in the environment. The male child demonstrated perseveration and preoccupation with sounds and textures, but had no abnormalities in social interaction. Although both children showed developmental disabilities, the degree of cognitive delay was significantly less than that described in previous reports of children with Joubert syndrome. This report adds to the growing body of evidence implicating cerebellar involvement in developmental disabilities and autistic behavior.

Familial Alzheimer disease: a large, multigeneration German kindred

A German family with 21 members affected by Alzheimer disease (AD) was studied clinically and genetically. The diagnosis was histologically verified in three affected family members. Ancestors were traced through seven generations to a couple residing in East-Westfalia during the middle of the 19th century. Dementia was often accompanied by extrapyramidal features and myoclonus. No cases of Down syndrome or hematologic malignancy occurred in this family. Clinical manifestations, temporal progression, neurological testing, and neuropathological features do not differ from the more common sporadic form of AD. The inheritance pattern is most consistent with autosomal-dominant transmission.

[Psychological adjustment to abortion for genetic indications in the 2d trimester]

Based on a questionnaire analysis of 41 women after termination of pregnancy for genetic indications in the second trimester of pregnancy the predominant feelings in the different stages of the coping process were identified. Whereas during the hospitalization period helplessness and anger were the predominant emotions, later sadness prevailed. At the time of the abortion itself loneliness was one of the main complaints. This situation could probably be improved if more often the partners were present during the period of abortion induction. About 54% of the women indicated that a prenatal diagnosis in the first trimester would have improved their coping problems. It remains to be seen whether CVS in the first trimester will be of benefit in this respect. Even though there are methodological limitations in a retrospective questionnaire study our results clearly underline the necessity of special psychologic support which can probably partly be provided by a psychologist who is available in our prenatal program.

17/7 translocation trisomy: practical vindication of a model of sickness

A girl was seen by a psychiatrist for relentless rubbing of her eyes and difficult behaviour. A proper diagnosis of her sickness required an understanding of the cause of her physical stigmata, which disclosed a previously undescribed chromosome anomaly (partial trisomy 17p); her mental handicap and behavioural disorder, which were partly a function of parental despair; and the predicament of her father and other carrier relatives who were identified through this child. Explanation or alteration of each component of sickness was necessary to achieve beneficial change.

Postnatal gonadal steroid effects on human behavior

Gonadal steroid hormones, active during fetal life, continue after the birth of a fetus to influence the central nervous system and affect behavior. The characteristically different circulating concentrations of male and female steroid hormones in men and women appear to be partial determinants of certain sexually dimorphic behaviors, interacting in a complex way with psychological and sociocultural factors as well as with other biological factors. This interaction is highlighted in research on testosterone and aggression in men, mood and the menstrual cycle in women, and pubertal sex role reversal in pseudohermaphrodites.

[Chromosome anomalies and their consequences for deviant behavior (author's transl)]

Chromosome anomalies are always accompanied by more or less serious behavior disorders. Yet deviant behavior in autosomal chromosome aberrations, especially the Down syndrome, on account of their severity and considerable reduction of intelligence of those affected, are far less important to the public than the gonosomal aberrations: the Klinefelter syndrome (XXY), the XYY syndrome, gonadal dysgenesis (Turner's syndrome, XO).