Multiplex quantitative fluorescent polymerase chain reaction for detection of aneuploidies

Quantitative fluorescent polymerase chain reaction (QF-PCR) is a well-established method in Western countries where commercial kits are being used for rapid prenatal diagnosis of aneuploidies. The limitations of these kits are that these are basically designed for the Caucasian population and are very expensive. Thus there is an urgent need to investigate the informative markers in the Asian population and to develop indigenous informative markers for detection of aneuploidies. This is a cost-effective alternate to the commercial kits and can be easily used in developing countries. We have tested three STR markers (D21S1435, D21S11, and D21S1411) in confirmed cases of Down syndrome and their parents. Origin of nondisjunction was also determined by means of QF-PCR. All the Down syndrome cases were confirmed for trisomy 21 by STR analysis. The results matched 100% with the karyotyping results. Nondisjunction was maternal in 87.5% cases and paternal in 12.5% cases. Nondisjunction during meiosis I was responsible for 87.5% cases of maternal nondisjunction and 100% cases of paternal nondisjunction. The combination of three STR markers is highly informative and can be used for diagnosis of trisomy 21 in India.