Sudden Death in Pediatric Patient With Dilated Cardiomyopathy Due to Founder Variant in NKX2-5: Case Report

Background: The NKX2-5 gene encodes a transcription factor that plays a role in atrioventricular nodal and myocardial development. Pathogenic variants of NKX2-5 are associated with congenital heart disease and sudden cardiac death. The missense variant in this case is one of the more common ones in Northern Europe and has high penetrance in familial cases. To our knowledge, this is the youngest person who died due to this variant. Case summary: This was a healthy, asymptomatic 14-year-old male with well-managed mild congenital dilated cardiomyopathy who died unexpectedly in his home. Postmortem examination revealed the NKX2-5 pathogenic missense variant, p.Phe145Leu, as the only explicable cause of death. Discussion: We propose that immediate family members of those who die suddenly due to NKX2-5 disease undergo genetic counseling and longitudinal screening to include this gene, as pathogenic variants in the NKX2-5 gene may manifest in a time-dependent manner.