Complex segregation analysis of hypospadias.

Hypospadias, when the urethra opens on the ventral side of the penis, is a common malformation seen in about 3 per 1000 male births. It is considered a complex disorder with both genetic and environmental factors involved in the pathogenesis. Low birth weight is known to be an important risk factor for hypospadias, but several observations speak in favour of genetic factors as well.

Heredity of hypospadias and the significance of low birth weight.

Purpose: We analyzed a large group of patients with hypospadias regarding familial aggregation, phenotype, twin rate and ethnic origin and assessed the correlation of low birth weight with hypospadias.

Materials And Methods: We mailed questionnaires to 2,503 boys operated on for hypospadias in Sweden asking for additional cases of hypospadias in the family, the number of brothers in the nuclear family, and birth weight of the boys with hypospadias and their brothers.

Results: Of the boys 7% reported 1 or more additional family members with hypospadias.