Incidence of the Hb E [β26(B8)Glu→Lys, GAG>AAG] Variant In Totos, One of the Smallest Primitive Tribes in the World

Abstract

Toto is one of the smallest tribes in the world. This primitive sub Himalayan, endogamous tribe lives in a small, isolated village called Totopara in the Jalpaiguri district of West Bengal in India. The tribal communities of West Bengal are vulnerable to various genetic disorders such as β-thalassemia (β-thal). We have studied 443 Totos to define their Hb E [β26(B8)Glu→Lys, GAG>AAG] status. Awareness and screening camps have been organized in various parts of Totopara during the last 2 years. We collected 3 mL peripheral blood from each individual aseptically on which to use the naked eye single tube red cell osmotic fragility test (NESTROFT); complete hemogram and high performance liquid chromatography (HPLC) were done to detect their carrier status. The Hb E variant had been found to be prevalent among the Totos. To confirm the codon 26 (GAG>AAG) mutation in the β-globin gene, amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) was performed. Restriction fragment length polymorphism (RFLP)-PCR was carried out with 44 Hb E alleles to construct the haplotype(s) of the Totos. Our extensive studies have revealed that 49.21% of Totos are Hb E heterozygotes and 19.19% Totos are Hb E homozygotes. The most prevalent haplotype linked with the codon 26 mutation in the Totos is [+ − − − − −] (HincII 5′ϵ, HindIII ^Gγ, HindIII ^Aγ, HincII 5′ψβ, HincII 3′ψβ and HinfI 3′β). Consanguineous marriages have resulted in a significant increase of the percentages of heterozygotes and homozygotes of Hb E in the Totos. Genetic counseling is essential and important to prevent the spread of this mutation and hence to save them from having any kind of clinically significant hemoglobinopathy in the future.

• Haplotype
• Hb E heterozygote
• Hb E homozygote
• Primitive tribe
• Toto
• β-Thalassemia (β-thal)

View correction statement:

Correction to: Incidence of the Hb E [β26(B8)Glu → Lys, GAG > AAG] Variant in Totos, one of the Smallest Primitive Tribes in the World

ACKNOWLEDGMENTS

We would like to thank Mr. Priyabrata Das (NCRI, Kolkata, West Bengal, India) for his extensive support. We convey our gratitude to Mr. M.G. Hira, Additional District Magistrate of Jalpaiguri, West Bengal, India, and Dr. Malay Kumar Ghose, Chief Medical Office of Health, (Jalpaiguri District Hospital), for their kind cooperation. Mr. Bhakto Toto, Community leader, Mr. Dhaniram Toto, Social worker, Mr. Subhash Mondal, Pharmacist of Primary Health Centre at Totopara, Mr. Harendranath Saiba, Mrs. Misha Ghoshal and Mr. Buddha Toto (United Commercial Bank, Totopara, Jalpaiguri District) are also acknowledged with gratitude for their constant support and help. We wish to acknowledge all the Totos who participated in this study. We would also like to thank Mr. Arnab Dutta, Mr. Sukanta Konar, Mr. Atul Das and Mrs. Shyamali Ganguly (NCRI) for their effort to successfully arrange the camps at Totopara. Last but by no means least, we thank the NCRI sister and laboratory technicians who helped us to complete this challenging job.

Declaration of Interest

We are grateful to the Department of Biotechnology, Government of India, New Delhi, India for their financial assistance (Sanction No. 102/IFD/DBT/SAN/PR-1468/2008-09, dated 14 October 2008). The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.