Noninvasive prenatal testing for fetal aneuploidy and single gene disorders.

Our concept of nucleic acid biology has advanced dramatically over the past two decades, with a growing appreciation that cell-free DNA (cfDNA) fragments are present in all body fluids including plasma. In no other field has plasma DNA been as rapidly translated into clinical practice as in noninvasive prenatal testing (NIPT) for fetal chromosome abnormalities. NIPT is a screening test that requires confirmation with diagnostic testing, but other applications of cfDNA provide diagnostic information and do not require invasive testing. These applications are referred to as noninvasive prenatal diagnosis (NIPD) and include determination of fetal sex, blood group and some single gene disorders. As technology advances, noninvasive tests based on cell-free nucleic acids will continue to expand. This review will outline the technical and clinical aspects of NIPT and NIPD relevant to the daily practice of maternity carers.