The role of sexual related Y gene detection in the diagnosis of patients with gonadal dysgenesis

Objective To clarify the role of sexual related Y (SRY) gene detection in t he diagnosis of gonadal dysgenesis. Methods Sixteen cases of gonadal dysgenesis were included in this study: 5 with androgen insensitivity syndrome, 1 with 17-alpha -hydroxylase deficien cy, 4 with true hermaphrodite, 2 with 45, X/46, XY gonadal dysgenesis, 1 wi th 45,X gonadal dysgenesis, 1 with XY pure gonadal dysgenesis, 1 with testi cular regression, and 1 XY female who gave birth to a normal baby. SRY gene was detected by using polymerase chain reaction (PCR) in blood and gonad s amples and by direct sequencing of the SRY motif. Results Among the 16 cases, 15 were blood SRY positive, among which 13 (86. 7%) showed the presence of testicular tissue, and 2 showed ovaries without testicular tissue. One SRY negative case showed the presence of testicular tissue. In 3 cases, SRY detection in gonadal tissue correlated with patholo gical findings but not with blood karyotype. The correlation between periph eral blood SRY and the pathology of the gonads was 81.25% and the correlati on between the presence of peripheral blood Y chromosome and pathology of t he gonads was 68.75%. Sequencing of the SRY motif in an XY female who gave birth to a normal baby showed no mutation. Conclusions SRY detection is more sensitive and specific than blood karyoty pe in the prediction of the presence of testicular tissue. Peripheral blood karyotype does not necessarily reflect gonadal type. There may be testicul ar related factors other than the SRY gene.