[Mixed gonadal dysgenesis. Apropos of a series of 21 cases]

Twenty-one cases of mixed gonadal dysgenesis referred at age 1 to 16 years are studied. External genitalia were in most cases of types III-IV, with a small penis and posterior hypospadias, asymmetrical genital folds containing an externalized testis on one side. The internal genitalia varied according to the degree of dysgenesis of the gonads, and included an uterus and/or a vagina in 18 among the 21 cases. A chromosomal mosaicism XO/XY or XX/XY was found in 11 patients, the other 10 having a normal 46 XY caryotype. Pubertal follow-up was obtained in 10 cases, and showed always a male sexual development, without possibility to exactly evaluate the function of the testis. Choosing the sex assignment is relatively easy in newborns or infants with mixed gonadal dysgenesis. It relies more on anatomy (size of corpora cavernosa, feasibility of urethroplasty or vaginoplasty) than on the results of hormonal measurements. The presence of an Y chromosome is not by itself an argument to choose the male sex. In most cases, the choice of the female sex is the easiest and relies on strong clinical arguments, but it leads unavoidably to suppress both the testis and the dysgenetic gonad.