Use

Chromosome Analysis using chorionic villus sampling (CVS) provides prenatal diagnostic information regarding fetal chromosomal abnormalities. It detects numeric and structural chromosomal alterations, such as trisomies (e.g., Down syndrome [trisomy 21], trisomy 18, trisomy 13), sex chromosome abnormalities (e.g., Turner syndrome, Klinefelter syndrome), rearrangements (Robertsonian translocations, inversions), marker chromosomes, and mosaicism at or above approximately 14% at a 95% confidence level. It does not detect microdeletion syndromes below cytogenetic resolution (e.g., DiGeorge, Prader–Willi, Angelman, Williams), fragile X syndrome, single-gene disorders, or cryptic gains/losses. If mosaicism or microdeletion syndromes are suspected, additional testing (e.g., microarray) may be appropriate.