CYP21A2 and congenital adrenal hyperplasia: German guidelines recommend prenatal diagnosis in the following cases: (1) Families with one affected child (index case) with classic CAH (CYP21A2); (2) Known parental heterozygosity for classic CAH (no index case) (3) New relationship of a parent of a child with classic CAH if the new partner is known to be a carrier for classic CAH; (4) Homozygosity or compound heterozygosity for classic CAH of one parent when the other parent is a heterozygous gene carrier for classic CAH (35).