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Disease Markers
Volume 22, Issue 5-6, Pages 327-334

Remarkable Variation in the Informativeness of RFLP Markers Linked to Hemophilia B Locus in Indian Population Groups: Implication in the Strategy for Carrier Detection

S. Mukherjee,1 A. Saha,1 Senthil Kumar P.,1 G. R. Chandak,2 P. P. Majumder,3 and K. Ray1

1Human Genetics and Genomics and Division, Indian Institute of Chemical Biology, Kolkata, India
2Genome Research Group, Centre for Cellular and Molecular Biology, Hyderabad, India
3Indian Statistical Institute, Kolkata, India

Received 18 January 2007; Accepted 18 January 2007

Copyright © 2006 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Hemophilia B, an X-linked recessive bleeding disorder, is caused by heterogeneous mutations in the factor IX (F9) gene. Hence, carriers of the disease are usually detected by F9 gene linked RFLP analysis. We aimed to test a set of RFLP markers (DdeI, XmnI, MnlI, TaqI & HhaI), used worldwide for carrier detection, to estimate its heterozygosity in different population groups of India, and identify additional single nucleotide polymorphisms (SNPs) if necessary. A total of 8 population groups encompassing different regions of India, consisting of 107 unrelated normal females without any history of hemophilia B in the family and 13 unrelated obligate carriers were recruited in the study. Regions of F9 gene were amplified by PCR from genomic DNA of the donors followed by restriction enzyme digestion and/or sequencing as appropriate. Combined informativeness for the markers varied between 52–86% among normal females belonging to different geographical locations of India. Haplotype analysis revealed that the most prevalent haplotype lacked the restriction sites for all five RFLP markers. Screening regions of F9 gene that harbor 10 SNPs reported in dbSNP yielded only two SNPs, which increased the overall informativeness in each population group and heterozygosity in the obligate carriers for the disease from 38% to 69%. Our data show that heterozygosity of commonly used RFLP markers is remarkably variable across different regions of India. Thus prudent selection of the markers based on specific population groups including usage of additional markers is recommended for efficient carrier detection.