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Title: Abnormalities of sex chromatin, with particular reference to the triple-X and chromatin-positive Klinefelter's syndromes in mental defectives
Author: Fraser, Jean H.
Awarding Body: University of Glasgow
Current Institution: University of Glasgow
Date of Award: 1964
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Abstract:
The historical background of chromosome investigation and nuclear sexing is reviewed, and the normal human karyotype and sex chromatin findings in man are described. The principles of chromosome analysis and the techniques for the investigation of nuclear sex are indicated. An outline is given of the various fields of research in which nuclear sexing methods have been applied in man. There follows a discussion concerning the anomalies of nuclear sex and sex chromosomes which have been detected by those techniques in various intersex states. The condition of chromatin positive Klinefelter's syndrome is then reviewed with particular reference to the incidence of the anomaly and its association with mental deficiency. The chromosomal variants of this syndrome are discussed in detail. Two cases, of the XXXY and XXXXY variants are described and compared with other similar chromosomal variants reported in the literature. These variants are reviewed and the effect of extra X and Y chromosomes are discussed with regard to the production of mental deficiency. Gonadal and somatic anomalies, and the formation of specific clinical syndromes are also considered, It is demonstrated that an increase in the number of X chromosomes increases the severity of the gonadal abnormality, the degree of mental deficiency and the frequency of associated congenital abnormalities of the skeleton and soft tissues. It is shown that in the XXXXY chromosomal variant a clinical syndrome is produced distinct from the commonly encountered XXY from of the syndrome. The results of two surveys of female mental defectives carried out by the buccal smear technique are given. In these the incidence of the triple-X anomaly was found to be 0.67% in 595 inmates of a mental deficiency institution and 0.28% in 711 mentally handicapped schoolchildren. The results of surveys by other workers of the incidence of this chromosome anomaly in mental defectives and in the general population are then considered in relation to the above. The clinical features of the six triple-X subjects detected in my two surveys are described j, and it is shown that there are no features forming a specific clinical syndrome. Other cases of the triple-X anomaly which have been reported in the literature are reviewed and the above finding confirmed. The effect of extra X chromosomes in the female is discussed and it is demonstrated that mental deficiency, although present in the majority of cases, is not a necessary accompaniment of the triple-X anomaly. It is also shown that in some subjects, including one of mu triple-X eases, fertility la not affected;, and that the offspring need not be chromosomally abnormal. The effect of maternal age in the production of chromosomal anomalies is discussed" Finally, the hypotheses concerning the derivation of sex chromatin and drumsticks are considered, and it is shown how the study of nuclear sex and sex chromosomes in normal and abnormal clinical conditions has led to the formulation of these present hypotheses.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (M.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.776737  DOI: Not available
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