It is important to understand what congenital adrenal hyperplasia (CAH) is before the nature of 11 beta hydroxylase deficiency can be fully explained. CAH refers to any one of the many autosomal recessive illnesses that result from flaws in cortisol synthesis steps done by the adrenal glands. All of the types of CAH have either overproduction or malfunctioning of sex steroids. 11 beta hydroxylase deficiency is just one of the types of CAH and is a result of mutation in the gene called CYP11B1. This type is next only to 21-hydroxylase deficiency when it comes to its prevalence, comprising only 5-8% of the entire number of cases.