[Fluorescence diagnosis of a lengthened Y-chromosome in father and son]

Two cases with long Y chromosome in a father and his son have been described. The chromosomes were analysed routinely using the peripheral blood leukocyte culture according to Moorhead et al. (1960) and of the slightly modified fluorescence method of Caspersson (1970, 1971) after QM-staing. In both patients the size of the Y resembled that of the pair 17--18 of autosomes. A brightly fluorescent heterochromatic region of the Y showed normal patterns and size. In one of the patients the analysis of solar and palmar dermatoglyphics, the testicular biopsy, EEG, glucose loading test, as well as laboratory tests evaluating the hormonal function of adrenal cortex and of thyroid gland were performed. The second patient did not agree to any tests.