Abnormality of the X chromosome in human 46,XY female siblings with dysgenetic ovaries.

An abnormal extra band was found on the short arm of the X chromosome in a 46,XY female and in her 46,XY female fetal sibling. Despite presence of the intact Y chromosome, there was no evidence of testicular differentiation in either subject. Production of H-Y antigen was suppressed in both subjects. The data suggest that development of the mammalian testis requires a normal function of the X chromosome.