Diagnosis of trisomy 21 in preimplantation embryos by single-cell DNA fingerprinting.
Many couples presenting for preimplantation genetic diagnosis (PGD) for a single gene disorder are of advanced reproductive age (>35 years) and have a greater chance of producing embryos with chromosomal aneuploidies. The most common chromosomal aneuploidy observed in newborns is trisomy 21, or Down's syndrome. Consequently, the availability of a highly reliable system that simultaneously detects the heritable gene disorder and trisomy 21 would be beneficial to couples at specific risk. A pentaplex chromosome 21 (Ch 21) single-cell DNA fingerprinting system was developed in a multiplex fluorescence polymerase chain reaction (FL-PCR) on single cells. High reliability and accuracy rates were observed, together with low allele dropout (ADO) and preferential amplification rates on diploid buccal cells, trisomy 21 buccal cells and blastomeres derived from Ch 21 aneuploid embryos. A combined multiplex FL-PCR format was optimized with the common cystic fibrosis delta F508 mutation and validated on single buccal cells from a carrier of the cystic fibrosis delta F508 mutation. This new test is a very powerful technique, which also allows confirmation of the embryo parentage and the identification of extraneous DNA contamination that could cause a misdiagnosis in PGD cases.
Katz
M G
MG
Monash Institute of Reproduction and Development, Monash University, Clayton, Victoria, Australia. mandy.katz@med.monash.edu.au
Mansfield
J
J
Gras
L
L
Trounson
A O
AO
Cram
D S
DS
D001755:Blastocyst; D002891:Chromosomes, Human, Pair 21; D016172:DNA Fingerprinting; D004314:Down Syndrome / Q000175:diagnosis* / Q000235:genetics; D005819:Genetic Markers; D006801:Humans; D018895:Microsatellite Repeats; D009061:Mouth Mucosa / Q000166:cytology; D016133:Polymerase Chain Reaction; D019836:Preimplantation Diagnosis / Q000379:methods*
D005819:Genetic Markers