Absence of mutations in the second exon of the steroid 5α-reductase type 2 gene in two highly inbred lambs affected by hypospadia

Hypospadias are the most frequent human penile abnormality. They have a genetic basis, even if environmental factors such as low birth weight, and exposure to hormones and to endocrine disruptors during pregnancy are not totally discarded.In sheep, the variable incidence in different breeds and a coincident occurrence in a couple of twins have suggested a possible genetic origin. We are presenting a detailed study of hypospadia in two rams. In both cases, high inbreeding supports a genetic origin for this pathology. A preliminary analysis on the second exon of the 5α-reductase 2 did not provide evidences for mutations in these individuals, even if they are often responsible for hypospadias in humans.