HSD3B1is a humangenethat encodes for a3beta-hydroxysteroid dehydrogenase/delta(5)-delta(4)isomerasetype I orhydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase 1. While it can carry out the same function asHSD3B2, it localizes primarily to different tissues, such as theplacentaand nonsteroidogenic tissues. Its requirement for the production ofprogesteroneby the placenta, which has a vital role in pregnancy, may be one reason why no disease based on mutations in this gene has been identified to date.
