Megaconial congenital muscular dystrophy (MDCMC) is an ultra-rare childhood neuromuscular disorder caused by biallelic pathogenic variants in the CHKB gene, which encodes choline kinase β — an essential enzyme in phospholipid biosynthesis and mitochondrial structure maintenance. While many CHKB mutations have been reported, the functional impact of splicing-related variants has remained insufficiently understood.

A new study by Cotrina-Vinagre et al. reveals that multiple rare CHKB variants cause aberrant RNA splicing, leading to exon skipping, truncated proteins, and unstable transcripts subject to nonsense-mediated decay. Using whole-exome sequencing and RT-PCR from patient lymphocytes, researchers identified several novel splicing defects that eliminate critical coding domains required for CHKB enzymatic function.

These findings provide functional confirmation that altered RNA processing is a major disease-driving mechanism in MDCMC. The resulting CHKB loss disrupts phospholipid biosynthesis, damages mitochondrial morphology, and compromises membrane stability in muscle fibers — hallmarks of the megaconial phenotype.

By mapping the precise molecular consequences of splicing variants, this research expands the known pathogenic mechanisms in CHKB disease and highlights opportunities for future therapeutic strategies, including gene replacement and RNA-targeted correction.

Stay informed as gene therapy advances create new possibilities for treating CHKB-related neuromuscular diseases. Explore our research and development programs.