Molecular genetic study on gene polymorphism of Kidd blood group system of voluntary blood donors in Shenzhen Han population

Objective To explore the molecular genetic background of the Kidd blood group gene polymorphism of voluntary donors in Shenzhen Han population. Methods From January 2015 to December 2015, a total of 74 voluntary blood donors of Han nationality in Shenzhen Blood Center were selected into this study by simple random sampling method. Blood samples from all these donors were detected by urea solution hemolysis test of red blood cell and routine serological method, in order to identify the Kidd blood group phenotypes of donors. Genomic DNA covering exon 4-11 and partial introns of JK gene was amplified by PCR, and amplification products were directly sequenced. Results ① The Kidd blood phenotypes of 74 donors were 37 cases of Jk (a+ b+ ), 16 cases of Jk (a+ b-), and 21 cases of Jk (a-b+ ). ② Exon 4-5, exon 6, exon 7, exon 8-9, exon 10 and exon 11 of JK gene were successfully amplified from DNA samples of these 74 donors. ③The JK gene of 37 samples of Jk (a+ b+ ) carried 2 kinds of heterozygous mutations, including exon 9 c. 838G>A and intron 7 c. 664-68C>T. The JK gene of 21 samples of Jk (a-b+ ) were homozygous for exon 9 c. 838AA and intron 7 c. 664-68TT, and 16 samples of Jk (a+ b-) were homozygous for exon 9 c. 838GG and intron 7 c. 664-68CC. Intron 8 c. 811+ 84TT was found in all 74 samples. Conclusions In the Kidd blood system of Shenzhen Han blood donors, the mutations of exon 9 c. 838G>A (p.Asp280Asn) and intron 7 c. 664-68C>T may be associated with JKa/JKb gene polymorphism. Homozygous genotypes for Intron 8 c. 811+ 84TT in JK gene were in all 74 blood donors, and homozygous for intron 8 c. 811+ 84TT in JK gene is common allele in Shenzhen Han population. Key words: Kidd blood-group system; Polymorphism, single nucleotide; Sequence analysis; Chinese Han population