NKX2-5 Gene Variants Associated with Congenital Heart Defects in Turkish Population

Introduction: Congenital heart defects (CHDs) are the most common congenital anomaly of the newborn with high mortality and morbidity rates. Genetic and environmental risk factors have affect on cardiogenesis. NKX2-5 (NK2 homeobox 5) is a homeobox containing gene which is essential for cardiac differentiation. In this study, our aim was to detect NKX2-5 gene variants associated with CHDs in Turkish population and to better understand genotype- phenotype correlations. Materials and Methods: In this study, we designed primers specific for NKX2-5 gene and sequenced the gene in 80 isolated CHD and 50 control group patients. Patients with chromosomal anomalies, DiGeorge syndrome and multiple congenital anomalies were not included. Results: Most common CHDs seen in the patients were ventricular septal defects (VSD) and atrial septal defects (ASD) (20%), atrioventricular septal defects (AVSD) and tetralogy of Fallot (TOF) (8.75%). We have detected NKX2-5 gene variants in 3.75% of the patients. We found A119S, R161P and C270Y changes in TOF; PFO (patent foramen ovale) with transient supraventricular, ventricular arrhythmia; and ASD patient, respectively. Conclusion: This study is designed to contribute to the genetic variations associated with CHD in Turkish population. NKX2-5 gene R161P variant which is on homeobox domain, was previously reported as pathogenic in an individual with thyroid ectopy and PFO. Further studies are needed to evaluate a possible role of these changes. Genetic testing is important in the follow-up and treatment of patients.