Scant XYqh- testicular cells with normal SRY was enough to differentiate bilateral testes in a 45,X/46,XYqh- patient

OBJECTIVE: It has been established that in 45,X/46,XY individuals predominance of XY or XO gonadal cells determines gonadal differentiation. However, in some cases there is no concordance between the predominance of XY cells and testis differentiation. Here we describe the SRY findings in a patient bearing a 45,X/46,XYqh- karyotype. STUDY DESIGN: The patient presented two small testes (one with spermatogenesis), a male phenotype, and a predominant 45,X karyotype in leukocytes and gonadal cells. PCRs of SRY, ZFY and Yqh were performed on DNA from leukocytes and from left gonadal tissue. SRY-PCR products were purified and sequenced. RESULTS: A normal SRY sequence was found in both tissues. CONCLUSIONS: Despite the predominance of 45,X cells in gonads, some patients in whom SRY is normal can develop testes, probably due to the presence of alternative mechanisms involved in testicular differentiation; however, further gonadal development could be impaired.