Hypospadias is a congenital defect, which affects normal development of the male urogenital external tract. In this malformation, the urethral orifice of the penis is positioned ventrally, thus interfering with normal urination and creating, in some adults, problems during sexual intercourse. Heritability of hypospadias has been shown in some reports, and the abnormality has been associated with the presence of mutations in one of the genes involved in urogenital development. However, even for patients who were born in families with a higher incidence rate of this
defect, no evident genetic alteration could be identified in known genes, indicating that the list of loci involved is still incomplete. To further complicate matters, recent reports also underline that epigenetic changes, without any identifiable gene sequence mutation, may be involved in gene function impairment. Therefore, the inheritance of most hypospadias cases is not evident, suggesting that the genetic background is not the only cause of this malformation; indeed, the majority of hypospadias cases are classified as sporadic and idiopathic.