Gonadal function in Bloom's syndrome.

Five patients with Bloom's syndrome aged from 2 8/12 to 27 years, all of whom had hypogonadism, were subjected to an i.v. LHRH test and two of them to an i.m. HCG test. There was increased responsiveness of plasma LH and FSH, indicating that the hypogonadism is primary in nature and of early development. The tubular element of the testis seems to be mainly affected, as indicated by the particularly high FSH response to LHRH stimulation, a history of sterility in the two adult patients and documented azoospermia in one of them. The Leydig cells seem to be less affected and secrete sufficient androgens to enable puberty within acceptable normal limits. Hypogonadism seems to be a major characteristic of Bloom's syndrome.