We have refined polymerase chain reaction (PCR) assays for the
detection of sickle cell anaemia,
the delta F 508 deletion causing cystic fibrosis, and the IVS1–110
mutation leading to beta-thalassaemia, allowing them to be successfully
performed upon single cells using fluorescent primers.
We have also assessed the possibility of detecting aneuploidies of
chromosomes 13, 18 and 21 using
a quantitative fluorescent polymerase chain reaction (QF-PCR) with primers
flanking polymorphic
short tandem repeat (STR) markers. Trisomies were readily diagnosed by
the
detection of tri-allelic
patterns. However some heterozygote normal and trisomic diallelic patterns
did not produce the
expected ratios of amplified PCR products due to preferential DNA sequence
amplification. Total
allelic drop out (ADO) did not occur with any of the cells tested.
Multiplex QF-PCR assays can be
performed on a single cell in under 6 h and simultaneously provide
diagnosis of single gene defects,
sex determination and an indication of selected chromosome aneuploidy.