Classic Congenital Adrenal Hyperplasia Due to 21-Hydroxylase Deficiency, Simple Virilizing Form, is also known as classic 21-ohd cah, simple virilizing form. An important gene associated with Classic Congenital Adrenal Hyperplasia Due to 21-Hydroxylase Deficiency, Simple Virilizing Form is CYP21A2 (Cytochrome P450 Family 21 Subfamily A Member 2). Affiliated tissues include uterus and bone.