[The value of cytogenetic investigations in the differential diagnosis of abnormalities in sex differentation (author's transl)].

This report is concerned with the scope of cytogenetic investigations in the diagnosis of sex abnormalities. In the majority of cases the karyotype leads to correct diagnosis only when the clinical picture and the histology of the gonads are known. It is only rarely possible to identify the phenotype from the chromosome picture, as for instance in the case of XO or XXY karotypes. Cytogenetic investigations can be considered advisable in the diagnosis of sex differentiation disorders in the following cases: a) in the case of ambiguous external sex organs; b) in primary amenorrhoea; c) in secondary amenorrhoea, above all in the case of early menopause; d) in male hypogonadism and in certain cases of gynaecomastia.