Detection of 13 Novel Variants and Investigation of Mutation Distribution by Next Generation Sequencing in Hemoglobinopathies: A Single Center Experience.

Abstract

Hemoglobinopathies are the most common monogenic disorders in the world. Traditional diagnostic algorithms generated by conventional methods for thalassemia can be labor-intensive and time-consuming due to the complexities of the genes involved and the variability in disease-causing mutations. With the advantages of next-generation sequencing (NGS) technology, molecular analysis of highly complex diseases such as hemoglobinopathies has become easier. Next-generation sequencing is a highly sensitive and effective method due to its capacity to sequence many gene regions simultaneously while allowing good read depths. In this study, single nucleotide changes, small deletions and copy number variations in HBA1, HBA2 and HBB in 914 patients with suspected hemoglobinopathy were analysed with NGS. At least one HBA1, HBA2, HBB or HBD variant was detected in 483 (52.8%) patients. Ten novel variants were detected in HBA1 and HBA2, three in HBB, and one in HBD. From these variants, c.*76T > A, c.301-24 G > A, c.301-24G > C c.-41C > G, c.-37-40C > G, c.-9G > C, c. 95 + 9C > T, c.95 + 26C > A, c.95 + 38C > T and c.*18C > G variants were located in α-globin genes, c.-25T > C, c.*103T > C and c92 + 39A > G variants were located in β-globin genes, and c.-43C > A was located in HBD. This is the first comprehensive study using NGS for the molecular diagnosis of hemoglobinopathies in Turkey. Accurate molecular diagnosis is of critical importance in hemoglobinopathies which are a public health problem due to their increased prevalence, high burden to society, and lack of curative treatment. Currently, NGS appears to be an advanced option over conventional methods to detect all variants occurring by molecular mechanisms and simultaneously analyse many genomic sequences.