MBTPS2 and IFAP syndrome: IFAP syndrome with or without BRESHECK syndrome (MIM#308205) is caused by pathogenic variants in the membrane-bound transcript factor protease site 2 (MBTPS2) gene, a zinc metalloprotease essential for cholesterol homeostasis and endoplasmic reticulum stress response.3 To date, nearly 60 cases of IFAP syndrome have been reported worldwide.