TMEM39B and autoimmune polyendocrine syndrome type 1: In addition to TMEM39B, the two final genes that were differentially expressed between APS-1 patients with the 13bp AIRE deletion and controls were GPSM3 and AKR1C3. AKR1C3, also known as 17β-hydroxysteroid dehydrogenase type 5 is a steroidogenic enzyme (17β-HSD5) capable of converting prostaglandins to metabolizing estrogen and progesterone.