Novel Non-invasive Prenatal Diagnosis as Related to Congenital Adrenal Hyperplasia

Abstract

Prenatal treatment of female fetuses having congenital adrenal hyperplasia (CAH) requires diagnosis of gender for genotype prior to genital differentiation. This approach currently involves chorionic villus sampling (CVS). In experienced hands CVS carries minimal risk of pregnancy loss, comparable to that associated with amniocentesis. Although offering considerable advantage by first trimester diagnosis, CVS is typically performed no earlier than 9-week gestation (7-week embryonic age) and usually not until 10–12 weeks. The procedure can be performed as early as 6–7 weeks, but it is technically difficult at that gestational age and associated with limb reduction defects. A preferable approach is definitive non-invasive diagnosis of fetal disorders. This could be achievable by analysis of either intact fetal cells or cell-free fetal DNA in maternal blood.