Aetiological studies of hypospadias in Hungary.

A complex aetiological (epidemiological, teratological and genetic) study was made in 294 index patients with simple isolated hypospadias. The epidemiological study conducted by the help of personal interviews of the mothers revealed a higher frequency of index patients among children born between August and December, among twins, mainly monozygotic, and finally in the lower birth weight groups and among first-borns. The teratological study showed a higher frequency in mothers of index patients who had had sex hormone treatment, mainly progestogen, before the 16th gestational week. This seems to indicate the aetiological role of fetal androgen deficit caused by the regulation disturbances of human choriogonadotropin. The genetic family study completed by personal examination of first-degree male relatives showed a familial clustering (4.0% versus a point prevalence of 0.44% in live-births). Both the pattern of affected relatives (h2 values 0.62 +/- 0.21 and 0.72 +/- 0.33 in fathers and brothers, respectively, not differing significantly from each other) and further characteristics (other malformations were not frequent in relatives) correspond to the multifactorial-threshold model.