Cryptorchidism is the absence of at least one testicle from the scrotum. It is the most common birth defect involving the male genitalia. It is associated with a higher risk of developing testicular tumors in adulthood. Studies in humans have investigated the possibility that mutations in the INSL3 gene are the cause of cryptorchidism. It has shown that INSL3 is involved in testicular descent, however, mutations of this gene are not a frequent cause of cryptorchidism.
