Preparation of chorionic villus samples for metaphase chromosome analysis and chromosomal microarray analysis

Chorionic villi are composed of an outer layer of trophoblastic cells and an inner mesenchymal cell core. They can be prepared for chromosome analysis using a culture method wherein villi are disaggregated by mechanical and enzymatic methods and the resulting cell suspension is used to establish primary cultures. Mesenchymal cells of the villus core are released by this procedure and the fibroblasts are actively proliferative in tissue culture. Cultures can be used for cytogenetic analysis after ∼1 week. Slides prepared by this technique can be stained using trypsin-Giemsa banding and analyzed for chromosomal abnormalities in fetal tissue. Chorionic villi may also be assessed by chromosomal microarray analysis (CMA). For this purpose, a method for extraction of high-quality DNA from CVS tissue is also described here.