Prenatal genotyping of Jk(a) and Jk(b) of the human Kidd blood group system by allele-specific polymerase chain reaction

An allele-specific polymerase chain reaction (ASPCR) assay for prenatal gen otyping of the Kidd antigen system in order to identify pregnancies at risk for haemolytic disease of the newborn (HDN) was developed. Oligonucleotide primers were designed for ASPCR of JKA and JKB. A validation study was per formed using DNA isolated from 54 serotyped whole blood samples and 8 amnio centesis samples. A concordance rate of 100 per cent was observed between s erotyping and ASPCR detection of the JKA and JKB alleles. Experiments were conducted to quantify the maternal contamination that could be tolerated in Kidd ASPCR assays. The sensitivity of this assay ranged from 0.2 per cent when detecting the presence of JKB and JKA background, to 2 per cent for de tecting the presence of JKA in a JKB background. This sensitive assay is pa rticularly useful for rapid genotyping of fetal amniotic cells to identify pregnancies at risk for HDN due to incompatibilities within the Kidd blood group system. Copyright (C) 1998 John Wiley & Sons, Ltd.