Kamla-Raj 2003                                                                           Int J Hum Genet, 3(1): 17-20 (2003)



DNA Diagnosis of Down Syndrome Using Polymerase Chain
Reaction and Polymorphic Microsatellite Markers


Sujoy Ghosh and S.K. Dey


Molecular Cytogenetics Laboratory, Department of Zoology, Presidency College, 86/1, College Street, Kolkata 700 073, West Bengal, India

E-mail: subrato_dey@sify.com


Key Words Down syndrome; trisomy 21;   polymerase chain reaction; microsatellite markers


Abstract  For antenatal diagnosis of Down syndrome (trisomy 21) and for the determination  of parental origin of nondisjoined chromosome,  we have evaluated  a simple PCR based  DNA  diagnostic  method  where polymorphic allelic fragments were resolved  in  6% polyacrylamide gel. Three families, DS5 , DS7 and  DS9 , each with a single child with trisomy 21 were studied ,using two polymorphic microsatellite markers D21S2055 and D21S11 located on the long  arm of the chromosome 21.Trisomy 21 was identified by the presence of three distinct alleles while the origin of nondisjunction was found to be maternal in  all  three  families. The PCR based DNA diagnostic method  was  found  to  be  sensitive,reproducible and most efficient  not only for diagnosis of trisomy 21, but also for tracing allelic transmission from  parents to the offspring.


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