RESUMO
OBJECTIVE@#To study the molecular genetic background of Diego blood group in Chinese Han population.@*METHODS@#A total of 2990 blood samples from unrelated blood donors were phenotyped for Dia and Dib by serological method. Twenty randomly selected samples of Di(a-b+) type and all of the samples of rare Di(a+b-) phenotype by screening were genotyped by PCR-SSP and direct DNA Sequencing.@*RESULTS@#Of the 2990 samples identified by serological method, 2821 were Di(a-b+), 167 were Di(a+b+) and 2 were Di(a+b-). All of the 20 randomly-selected samples with Di(a-b+) phenotype were DI2DI2 homozygote by PCR-SSP genotyping, with nucleotide C at nt position 2561 in exon 19 by direct sequencing of the DI gene. The 2 samples of rare Di (a+b-) phenotype were both the DI1DI1 homozygote, with nucleotide T at nt position 2561 in exon 19.@*CONCLUSION@#Our results indicate that the expression of Dia and Dib antigens in Chinese Han population most likely result from a single nucleotide T to C substitution at nucleotide position 2561 in exon 19 of the DI gene, which subsequently leads to an amino acid 854 change from Pro to Leu.