[Molecular screening for Vel- blood type and analysis of SMIM1 gene variants].

OBJECTIVE To screen for Vel- rare blood type donors and determine the frequency of SMIM1 c.64_80del allele in Yili Prefecture of Xinjiang, China. METHODS DNA pooling and PCR-sequence-specific primers (PCR-SSP) was conducted to screen individuals carrying the SMIM1 c.64_80del variant, and Sanger sequencing of SMIM1 exon 3 was carried out to verify the genotype of those with the variation. SMIM1 intron 2 was also sequenced to identify single nucleotide polymorphisms (SNPs) that may affect the expression of Vel antigen. RESULTS Among 3328 blood donors, 14 were identified as heterozygotes for the SMIM1 c.64_80del allele, its allele frequency was 0.21%; no homozygous SMIM1 c.64_80 deletions was found. For SNP rs1175550, all of the 14 individuals had an AA genotype, among whom 5 carried heterozygous 7111ins GCA variant in intron 2. CONCLUSION The allelic frequency of SMIM1 c.64_80del in Yili area is approximately 0.21%, which is reported for the first time.