Hypospadias (HYSP) is defined as a defect in the development of the ventral aspect of the penis along with an ectopic opening of the urethral meatus. It is thought to be due to a combination of genetic and environmental factors. Mutations in the androgen receptor gene (AR) have been found in patients with severe forms of hypospadias. It was also reported that MAMLD1 is a causative gene. MAMLD1 is an X-linked transcriptional co-activator, expressed in foetal Sertoli and Leydig cells around the critical period for sexual development.
