Genetics of Undescended Testis

Abstract

The occurrence of undescended testes could be confirmed in 1.5-4.0% of the fathers and in 6.2% of the brothers of index patients with true undescended testes. The pattern of the familial cluster fits into the gaussian-additive-multifactorial-threshold program. The value of heritability for the 1st degree male relatives is 0.67 .+-. 0.16. In siblings of index patients with undescended testes other congenital abnormalities do not occur more often. Bilateral (more severe) undescended testes are associated with a higher recurrence risk for siblings. The nosological identity of unilateral and bilateral undescended testes have shorter menses and a delay in menarche. Thus, the pituitary hypogonadism of mothers seems to be a predisposing factor for undescended testes in their sons.