POR and congenital adrenal hyperplasia due to cytochrome P450 oxidoreductase deficiency: Although one pair of POR mutations can impair all microsomal cytochrome P450 enzymes, each enzyme is affected to a different extent (depending on the locations of the POR gene mutations), resulting in high clinical variability of PORD, such as it has been reported that young girls or women only had incomplete pubertal development, primary amenorrhea, oligomenorrhea or infertility with or without skeletal malformations [2, 23, 25].