A simple, modified technique for direct chromosome preparation from chorionic villi

Chorionic villus sampling (CVS) has proved to be an elegant and safe technique for prenatal diagnosis of genetic diseases during the first trimester of pregnancy. Despite a number of obvious advantages, the wide application of direct cytogenetic analysis of CVS has been hampered by serious technical problems involving large numbers of incomplete metaphases and poor chromosome morphology. A chromosome preparation technique direct from CVS has been devised which involves modifications in the hypotonic and dissociation stages. It yielded satisfactory results in fifteen samples within 24 h of sampling. It is suggested that this simple, modified technique can provide complete chromosomal analysis within a short time for prenatal diagnosis of genetic diseases, and may be used as a routine method in cytogenetic laboratories.