PHENOTYPICAL EXPRESSION IN XX MALES CORRELATES WITH TESTICULAR RESPONSE TO EXOGENOUS CHORIOGONADOTROPIN IN EARLY INFANCY - DOES A VARIABLE DEGREE OF TESTICULAR FAILURE DETERMINE THE DEGREE OF GENITAL AMBIGUITY

The 46,XX male syndrome is characterized by the presence of testicular development in subjects who lack a Y chromosome. The majority of pati ents have male external genitalia without ambiguity; however, 10-15% s how diverse degrees of hypospadias. Testicular function is normal at b irth but deteriorates thereafter. However, it has not been clarified w hy some cases exhibit genital ambiguity. This study examined 10 affect ed patients, including 4 prepubertal (<1 year old) with hypospadias (1 glandular, 1 penile, and 2 penoscrotal). In all subjects, testicular function was evaluated by performing a stimulation with choriogonadotr opin. In the postpubertal individuals, basal and poststimuli testoster one were below the reference values. Prepubertal patients had age-appr opriate basal testosterone concentrations. All responded to the chorio gonadotropin challenge; however, the most significant response was obs erved in the patient with the glandular hypospadias, the second highes t response was presented by the patient with the penile hypospadias, w hile both patients with the penoscrotal hypospadias had the poorest re sponses. These results suggest that the degree of genital ambiguity is correlated with the impairment in testosterone response to choriogona dotropin in early infancy, indicating a defect in testosterone product ion in XX males with genital ambiguity.