OBJECTIVE: Studying gene diagnosis of trisomy 21 by means of quantitative polymerase chain reaction(PCR). METHODS: Polymorphic short tandem repeat(STR) at D21S11 served as the gene marker, and a pair of primers was synthesized. The samples from 11 normal subjects and 28 cases of trisomy 21 were analyzed by quantitative PCR. RESULTS: 10 normal subjects showed two bands with a ratio of 1:1, and a subject showed one band. Of 28 cases of trisomy 21, 24 cases showed two bands with a ratio of 2:1, 3 cases showed three bands with a ratio of 1:1:1, and 1 case showed one band. CONCLUSION: Polymorphic STR at D21S11 is a valuable gene marker for diagnosis of trisomy 21. Trisomy 21 can be diagnosed rapidly and accurately within 24 hours by quantitative PCR.
OBJECTIVE: Studying gene diagnosis of trisomy 21 by means of quantitative polymerase chain reaction(PCR). METHODS: Polymorphic short tandem repeat(STR) at D21S11 served as the gene marker, and a pair of primers was synthesized. The samples from 11 normal subjects and 28 cases of trisomy 21 were analyzed by quantitative PCR. RESULTS: 10 normal subjects showed two bands with a ratio of 1:1, and a subject showed one band. Of 28 cases of trisomy 21, 24 cases showed two bands with a ratio of 2:1, 3 cases showed three bands with a ratio of 1:1:1, and 1 case showed one band. CONCLUSION: Polymorphic STR at D21S11 is a valuable gene marker for diagnosis of trisomy 21. Trisomy 21 can be diagnosed rapidly and accurately within 24 hours by quantitative PCR.