Molecular characterization of weaker variants of A and B in Indian population--the first report.
OBJECTIVE
The ABO blood group system is extremely important blood group system in transfusion medicine and weaker variants of A and B are subgroups of the system. From a Country like India with 1.2 billion population sporadic reports detecting weaker variants of A and B serologically are published. Therefore the main objective of the present study is to identify weaker variants of A and B serologically and characterize them at molecular level.


METHODS
Eight samples which were referred to us for resolving discrepancies in forward and reverse grouping were first phenotype in our laboratory by standard serologic techniques for ABO blood groups. Molecular genotyping for the ABO locus was done by PCR-SSCP. Altered SSCP patterns were analysed by DNA sequencing. Sequencing of intron 6 and exons 1-5 was done in one sample each.


CONCLUSIONS
Nine rare alleles affecting the normal expression of A and B antigens have been identified among Indians. They were two Aw06, one A209, one Ax20, two O05, one O49, one O56 and one O19 alleles. This is the first report demonstrating molecular studies on weaker variants of A and B from India.
Department of Transfusion Medicine, National Institute of Immunohaematology (ICMR Unit), 13th Floor, New Multistoreyed Building, KEM Hospital Campus, Parel, Mumbai, India. Electronic address: sbtray@yahoo.co.in.
Sabita
S
Ray
Department of Transfusion Medicine, National Institute of Immunohaematology (ICMR Unit), 13th Floor, New Multistoreyed Building, KEM Hospital Campus, Parel, Mumbai, India. Electronic address: ajit5678@yahoo.com.
Ajit C
AC
Gorakshakar
Department of Transfusion Medicine, National Institute of Immunohaematology (ICMR Unit), 13th Floor, New Multistoreyed Building, KEM Hospital Campus, Parel, Mumbai, India. Electronic address: vasanthak2007@yahoo.co.in.
Vasantha
V
Kashivishwanathan
Department of Transfusion Medicine, National Institute of Immunohaematology (ICMR Unit), 13th Floor, New Multistoreyed Building, KEM Hospital Campus, Parel, Mumbai, India. Electronic address: snehu.agarwal25@gmail.com.
Snehal
S
Agarwal
Department of Hematogenetics, National Institute of Immunohaematology (ICMR Unit), 13th Floor, New Multistoreyed Building, KEM Hospital Campus, Parel, Mumbai, India. Electronic address: anitahnadkarni@yahoo.com.
Anita
A
Nadkarni
National Institute of Immunohaematology (ICMR Unit), 13th Floor, New Multistoreyed Building, KEM Hospital Campus, Parel, Mumbai, India. Electronic address: kanjakshaghosh@hotmail.com.
Kanjaksha
K
Ghosh
D000017:ABO Blood-Group System / Q000235:genetics*; D000483:Alleles; D044466:Asian People; D001771:Blood Banks; D001788:Blood Grouping and Crossmatching; D005091:Exons; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D007194:India; D010641:Phenotype; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D018807:Polymorphism, Single-Stranded Conformational; D017422:Sequence Analysis, DNA
D000017:ABO Blood-Group System
India; Molecular genotyping; Weaker variants of A and B