Another XYY phenotype

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.

The mental implications of sex chromosome aberrations

I have chosen as the subject for my Blake Marsh Lecture the influence of sex chromosome aberrations on intelligence, mental health and social adjustment. This subject provides a fascinating example of how a branch of research, beginning in the field of mental retardation, arrived at discoveries which proved to be of significance to quite other fields of psychiatry. Ten years ago we learned that sex-chromatin-positive males, that is, males with additional X chromosomes, at least in some cell lines, were more often encountered among the intellectually retarded than among the average population of males. Shortly after this we learned that the same was true of women with double Barr bodies, that is, women with more than the usual two X chromosomes, at least in some cell lines. Today we have facts showing that an abnormal sex chromosome complement may have an unfavourable effect on mental health, and this in several different ways; thus we know that it may contribute to the development of functional psychoses, and may even influence such a complex variable of behaviour as our ability to adapt ourselves to the laws of the community. Myself, I am convinced that study of aberrations in the sex chromosomes will prove to have a radical effect on large sections of psychiatric thinking.

Lymphocytoid lines from persons with sex chromosome anomalies

Permanent lymphocytoid cell lines have been established from patients with the XYY and XXY chromosome constitutions. Large amounts of these and other cell lines with genetic defects can be provided for various studies.