Combined Leydig cell and Sertoli cell dysfunction in 46,XX males lacking the sex determining region Y gene

We have evaluated 3 individuals with a rare form of 46,XX sex reversal. All of them had ambiguous external genitalia and mixed wolffian and müllerian structures, indicating both Leydig cell and Sertoli cell dysfunction, similar to that of patients with true hermaphroditism. However, gonadal tissue was not ovotesticular but testicular with varying degrees of dysgenesis. SRY sequences were absent in genomic DNA from peripheral leukocytes in all 3 subjects. Y centromere sequences were also absent, indicating that testis development did not occur because of a low level mosaicism of Y bearing cells. The subjects in this report demonstrate that there is a continuum in the extent of testis determination in SRY-negative 46,XX sex reversal, ranging from nearly normal to minimal testicular development.