Novel KCNK3 variant in a child with pulmonary arterial hypertension.

backgroundPathogenic variants in KCNK3 have been implicated in pulmonary arterial hypertension (PAH); however, the molecular mechanisms underlying this association remain insufficiently defined.

methodsWhole-exome sequencing was performed in a child with PAH and her mother. The impact of the identified variant on protein stability was evaluated using cycloheximide chase assays. Apoptotic activity in transfected cells was assessed through flow cytometry and western blotting analysis. RNA sequencing was conducted to identify signaling pathways associated with altered gene expression. Oxidative stress levels were examined using inverted fluorescence microscopy. Expression levels of NFE2L2 was quantified by quantitative real-time polymerase chain reaction and western blotting.

resultsA novel heterozygous KCNK3 variant (c.607G > C, p.G203R) was identified. The substituted glycine residue demonstrated high evolutionarily conservation, and in silico analysis predicted structural alteration of the protein. The p.G203R variant was associated with reduced KCNK3 protein stability and an increase in apoptosis in vitro. Transcriptomic analysis indicated enhanced vascular smooth muscle cell migratory potential in cells expressing the variant. Increased cellular OS and apoptosis were observed in cells expressing p.G203R KCNK3. Bioinformatic analysis identified NFE2L2 as a key downstream effector. Expression of NFE2L2 was reduced in pulmonary artery endothelial cells expressing p.G203R KCNK3, while overexpression of NFE2L2 partially reversed variant-induced apoptosis.

conclusionThis study identifies a novel KCNK3 p.G203R variant associated with PAH and provides mechanistic evidence supporting its pathogenicity. These findings expand the variant landscape of KCNK3 in PAH and offer insights into disease pathogenesis that may inform future targeted therapeutic approaches.