Mitochondrial Megaconial Phenotype

The mitochondrial megaconial phenotype is the defining pathological hallmark of CHKB-related muscular dystrophy. Loss of choline kinase beta disrupts normal phospholipid biosynthesis, leading to abnormal mitochondrial enlargement and peripheral accumulation of these organelles within muscle fibres.

Muscle biopsy typically reveals markedly enlarged, abnormally shaped mitochondria clustered at the edges of fibres, along with variable fibre size, mild dystrophic changes, and evidence of muscle membrane instability. These mitochondrial defects impair cellular energy production, contributing directly to muscle weakness, fatigue, and progressive functional decline.

Beyond skeletal muscle, mitochondrial dysfunction may also contribute to neurodevelopmental symptoms, cardiac involvement, and systemic metabolic abnormalities observed in CHKB deficiency.

Because the megaconial phenotype reflects a core biochemical defect rather than secondary degeneration, it represents a compelling therapeutic target. Restoring CHKB expression may correct mitochondrial morphology and function, offering potential to meaningfully alter disease progression.