MICA-STR genetic polymorphism in a southern Chinese population

Objective: To explore the short tandem repeat (GCT) polymorphism of exon 5 of MICA (MHC class I chain related gene A) gene in a southern Chinese population composed of 231 unrelated healthy individuals. Methods: GCT polymorphism of exon 5 of MICA gene was analyzed by fluorescent PCR/size-sequencing, MICA deletion (MICA * Del) was screened by PCR/SSP technique. Results: Allelic variants of MICA * A4, MICA * A5, MICA * A5.1, MICA * A6, MICA * A9 and MICA * Del were identified, the most frequent of which were MICA * A5 and MICA * A5.1 with gene frequencies 0.362 and 0.313% respectively. MICA * Del, observed in 3 cases which were all HLA-B48 positive, showed a gene frequency of 0.006. MICA-STR genotype distributions were consistent with Hardy-Weinberg equilibrium. Conclusion: MICA-STR allelic distributions of southern Chinese population are different from those found in other ethnic groups. In addition, the existence of a low frequency of MICA deletion was identified in this population.