5-Alpha-Reductase 2 Deficiency in Newborns: A Review

Abstract

Disorders of sex development (DSD) are mostly associated with gender ambiguity at birth and poses a real challenge in diagnosis. 5 alpha reductase 2 deficiency (5AR2D) is one such DSD associated with deficiency of a key male sex hormone called as Dihydrotestosterone (DHT) due to lack of 5 alpha reductase type 2 enzyme which converts testosterone to Dihydrotestosterone. This hormone is very vital for the development of external genitalia during embryogenesis, and the deficiency leads to partial or abnormal male external genitalia in the affected neonate. 5AR2D is due to mutation in steroid-5-alpha-reductase, alpha polypeptide 2 (SRD5A2) genes on chromosome 2, band p23. Clinical presentation of these children vary from normal male genitalia to a completely female genitalia. 5AR2D is associated with deficiency of DHT and normal or increased testosterone levels. Most of the children with 5AR2D are raised as females and gender conversion to male happens at around puberty due to masculine and voice changes caused by testosterone. Early diagnosis is beneficial in treating this problem. Elevated testosterone: DHT ratio with administration of beta human chorionic Gonadotropin (HCG) is the gold standard test in diagnosis of this defect. Most patients of 5 alpha reductase 2 deficiency are considered infertile, but with recent advancements in assisted reproductive techniques a few 5AR2D have been successful in giving birth to their offsprings.