Understanding the role of Krupple like factor 1 KLF1 mutations in association with hereditary persistence of fetal hemoglobin and thalassemia intermedia cases

Abstract

Hereditary persistence of fetal hemoglobin (HPFH) is an uncommon inherited condition that results in increased fetal hemoglobin (HbF) levels in adult life. HPFH results from either promoter mutations or large deletions affecting the human fetal globin (HBG1 and HBG2) genes; called non-deletional HPFH or deletional HPFH respectively. The aim of the study is to determine the spectrum of mutations in KLF1 and other related factors in HPFH and and#946;-thalassemia intermedia cases. In this study 19 HPFH cases have been studied and 68.4% (13/19) cases had KLF1 variants (benign as well as possibly damaging variants). Among five factors at least one or more factors were able to explain the cause of raised HbF level in HPFH cases. Significant differences were observed on comparing the mutant allele frequencies of the 3 polymorphisms in each of the 3 groups vis-à-vis the controls (plt0.001 for all), with the exception of HBS1L-MYB rs4895441 polymorphism, which did not show any significant difference in frequency between TI (p=0.185) and and#946;TT (p=0.461) versus controls. Among and#946;TT (4/13=13%) and TI (3/50=6%) cases one KLF1 promoter variant -148(GgtA) rs79334031 was found which could be one reason of raised HbF. Variant c.901CgtT (p.Arg301Cys) was found in 2 HPFH cases and present in second zinc finger domain of KLF1. Molecular modelling was done to understand differential binding affinity of this mutant. Structural analysis of the model reveals that this mutation (c.901CgtT (p.Arg301Cys) might affect the binding affinity of KLF1 gene with its and#946;-globin promoter sequence which in turn can lead to increasing HbF levels.Successfully cloned the KLF1 Zinc Finger Domain region in a specific expression vector and express the wild and mutant protein (p.Arg301Cys). Characterization of wild and mutant protein was done to explain the protein stability in mutant and we found that mutant protein is less stable as compared to wild type. newline