Genotype-phenotype correlations in recessive RYR1-related myopathies

Area of Science:

• Genetics
• Molecular Biology
• Neurology

Background:

• RYR1 mutations are a common cause of congenital myopathies.
• Dominant RYR1 mutations are linked to central core disease and malignant hyperthermia.
• Recessive RYR1 mutations are increasingly identified, but genotype-phenotype patterns are unclear.

Purpose of the Study:

• To investigate genotype-phenotype correlations in recessive RYR1 myopathy cases.
• To identify patterns in recessive RYR1 mutations and their associated clinical phenotypes.

Main Methods:

• Analysis of a combined cohort of 106 recessive RYR1 cases (14 unpublished, 92 reported).
• Examination of mutation types, locations, and clinical severity.

Main Results:

• Nearly 50% of cases were non-core myopathy related.
• Hypomorphic RYR1 mutations, reducing RyR1 expression, were enriched in severe phenotypes and non-central core myopathies.
• Non-hypomorphic mutations were found in MH/CCD hotspots and the channel pore's selectivity filter.

Conclusions:

• Loss of RYR1 protein function is a key predictor of disease severity.
• Decreased RYR1 expression may contribute to non-core myopathy pathology.
• Abnormal ion conductance through the RYR1 channel pore is implicated in recessive RYR1 myopathy pathogenesis.