HLA A*02 allele and B-associated haplotype diversity in Indians.
Human leucocyte antigen (HLA) A2 is the most heterogeneous allele at the HLA A locus, with approximately 56 different subtypes. Substantial heterogeneity in A*02 distribution has been observed in populations worldwide. HLA A2 allele distribution varies (4-25%) in different Indian populations and castes. HLA B40 is the most common allele associated with A2 haplotypes. In this study, molecular A*02 subtyping in Maratha (western Indian--Aryan) and Nadar (south Indian--Dravidian) caste groups using high-resolution polymerase chain reaction/reverse line strip/sequence-specific oligonucleotide hybridisation (PCR-RLS-SSOP) indicates the presence of 10 subtypes (A*02011, A*0203, A*0205, A*0206, A*0207, A*0208, A*0209, A*0211, A*0222 and A*0236) in variable frequencies. Moreover, A*0211-B*4006 was commonly observed among the north Indian Maratha caste and A*02011-B*4006 among the south Indian Nadar caste groups. HLA A*0211 is found frequently in this population and in Asian Indians, and has been reported with low frequencies in many other populations worldwide. A*0222 has been observed among Hispanics, while A*0236 has been observed exclusively among members of the Maratha caste. The findings demonstrate a substantial heterogeneity among the groups studied that may be a consequence of founder effect, racial admixture or selection pressure due to environmental factors.
Shankarkumar
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HLA Department, Institute of Immunohaematology (ICMR), 13th Floor, K.E.M. Hospital, Parel, Mumbai-400012, India. shankarkumar16@hotmail.com
D018703:Founder Effect; D018740:Genetic Heterogeneity; D014644:Genetic Variation; D015789:HLA-A2 Antigen / Q000235:genetics*; D015235:HLA-B Antigens / Q000235:genetics*; D006239:Haplotypes; D006801:Humans; D007194:India
D015789:HLA-A2 Antigen; D015235:HLA-B Antigens