The novel large duplication spanning exons 3-10 of the HSD17B3 gene that we report here in compound heterozygosity with the known p.R80Q leads to 17β-HSD-3 deficiency presenting as 46,XY Disorder of Sex Development.
17-β-Hydroxysteroid dehydrogenase type 3 (17βHSD-3) deficiency is a rare, but frequently misdiagnosed autosomal recessive cause of 46,XY disorder of sex development (DSD).
Mutations in the HSD17B3 gene are associated with a rare form of 46,XY disorder of sex development referred to as 17betaHSD3 deficiency (or as 17-ketosteroid reductase deficiency), due to impaired testicular conversion of Delta4-A into T. 46,XY patients with 17betaHSD3 deficiency are usually classified as female at birth, raised as such, but develop secondary male features at puberty.