Cell-Free DNA: Screening for Single-Gene Disorders and Determination of Fetal Rhesus D Genotype.

The use of cell-free DNA (cfDNA) for screening and diagnosis of single-gene disorders is an evolving technology, and its application at this time is limited. Invasive testing is currently recommended for the diagnosis of single-gene disorders. The limitations of cfDNA technology are most notable in clinical settings involving X-linked and autosomal recessive conditions, in part because maternal mutant alleles greatly outnumber those of fetal origin. Examples of single-gene disorders for which cfDNA has been used include skeletal dyplasias, cystic fibrosis, congenital adrenal hyperplasia, β-thalassemia, and muscular dystrophies.