Leydig Cell Hypoplasia due to Inactivating Luteinizing Hormone/Chorionic Gonadotropin Receptor Gene Mutation Presenting as a 46,XY DSD

Leydig cell hypoplasia (LCH) due to inactivating mutations of luteinizing hormone receptor gene (LHCGR) is a relatively rare form of 46,XY disorder of sex development (DSD). LCH is inherited in an autosomal recessive manner, which leads to aberration of Leydig cell differentiation and ultimately subnormal androgen production both pre- and postnatally. In males, two distinct phenotypes have been described in the literature depending on the degree of remaining activity of LHCGR. Leydig cell hypoplasia type 1 (LCH type 1) represents more severe form with 46,XY DSD while Leydig cell hypoplasia type 2 (LCH type 2) is more diverse with micropenis to several degrees of undervirilization. We identified one kindred with 27-bp insertion in exon 1 causing 46,XY DSD.