The Application of Clinical Genetics (Mar 2021)
A Novel Frameshift Mutation, Deletion of HBB:c.199_202delAAAG [Codon 66/67 (-AAAG)] in β-Thalassemia Major Patients from the Western Region of Uttar Pradesh, India
Abstract
Waseem Chauhan,1 Mohammad Afzal,1 Zeeba Zaka-ur-Rab,2 Md Salik Noorani3 1Department of Zoology, Aligarh Muslim University, Aligarh, India; 2Department of Pediatrics, Jawahar Lal Nehru Medical College, Aligarh Muslim University, Aligarh, India; 3Department of Botany, Jamia Hamdard, New Delhi, IndiaCorrespondence: Mohammad AfzalHuman Genetics and Toxicology Laboratory, Department of Zoology, Aligarh Muslim University, Aligarh, IndiaTel +919897839601Email [email protected]: Beta thalassemia is one of the most common inherited disorders in India with heterogenous clinical phenotypes from silent carrier to clinically severe ones. Our study aimed to characterize the mutation spectrum in thalassemia patients who are coming to the hospital for follow-up from the western region of Uttar Pradesh India.Patients and Methods: For the study, a case series of the retrospective bi-centre study was conducted. The patients from two thalassemia centers in the major hospitals (LLRMC Meerut, and JNMC, Aligarh administered by the Ministry of Health and Family Welfare (MoHFW)) in the Western Uttar Pradesh, India were considered for the study. A total of 77 blood samples were obtained from individuals (both related and unrelated) diagnosed with β-thalassemia after their consent. After DNA extraction, HBB gene amplification, mutation-specific polymerase chain reaction and gene sequencing were carried out to analyze the mutations.Results: In this study, seven different types of mutations were reported for the first time in Western Uttar Pradesh, India. A novel frameshift mutation, deletion of 4 nucleotides Codon 66/67 (-AAAG) in exon 2 region, is reported for the first time. IVS 1– 5 (G>C) and Codon 41/42 (-CTTT) are the most frequently reported mutations. The molecular spectrum for these two cases consists of 44 and 42 alleles out of 108 alleles, respectively.Conclusion: A total of 108 β-thalassemia alleles were studied from 46 homozygous and 31 compound heterozygous patients. All the individuals were from 20 districts of the Western Uttar Pradesh, India.Keywords: codon 41/42-CTTT, IVS I-5G>C, beta globin, mutation, beta-thalassemia major
