NKX2.5 coding exons sequencing reveals novel non-synonymous mutations in patients with sporadic congenital heart diseases among the Tanzanian population

Abstract

BackgroundThe evolutionally conserved homeobox transcription factor NKX2-5 has been at the forefront in the field of cardiac biology, providing molecular insights into the mechanisms of cardiac development and disease. This homodomain transcription factor is a central regulator of cardiac development and is expressed in both the first and second heart fields (FHF and SHF). Mutations in the NKX2-5 gene have been linked to sporadic cases of congenital heart disease (CHD), making it a significant target for research and study. While several studies have been conducted on Caucasian populations, there is a dearth of knowledge on the effects of NKX2-5 gene mutations in other settings, underscoring the need for further investigation. Due to differences in geographical and ancestral origin, we hypothesize that mutations may vary across different populations. Understanding the genetic factors that cause CHD is essential for providing effective genetic counseling and developing strategies for risk reduction. Additionally, identification of NKX2-5 mutations in individuals with CHDs is crucial because patients with CHDs are at a higher risk of progressive conduction disease and sudden cardiac death, and genetic information is taken into consideration while making decisions regarding pacemakers and implantable cardiac defibrillators. To determine the risk of congenital heart disease among infants, we conducted a study where we sequenced the exon 1 and exon 2 of NKX 2.5 in patients with sporadic CHDs, with the aim of identifying mutations in the NKX2.5 gene.ResultsIn this study, a novel frame-shift disease-causing mutation was discovered in patients with atrial-ventricular septal defect. The mutation, identified as c95_95 del A; cDNA.369–369 delA; g 369–369 delA, resulted in the substitution of phenylalanine to leucine (F295L), which in turn caused a truncated NKX2.5 protein. In addition, a non-synonymous mutation, g 316C > T; cDNA 316C > T leucine to arginine (L37R) substitution, was found in a patient with the tetralogy of Fallot, affecting protein function. Furthermore, a novel non-synonymous mutation identified as g 2295–2298; cDNA 755–758 delins AGGG, was predicted by mutation taster to be disease-causing in a ventricular septal defect. It is worth noting that none of these mutations were found among the control subjects, highlighting their potential significance in the pathogenesis of these cardiac defects.ConclusionMutations in the NKX2.5 gene are associated with congenital heart diseases and provide molecular insight into the pathogenesis of congenital heart diseases. We recommend that patients with NKX2.5 mutations have periodic screening for cardiac conduction abnormalities and be evaluated for potential implanted cardiac defibrillators and pacemakers.