McArdle disease: a clinical review

Area of Science:

• Biochemistry
• Genetics
• Neurology

Background:

• McArdle disease is a rare genetic disorder affecting muscle energy metabolism.
• Understanding its clinical spectrum is crucial for diagnosis and management.

Purpose of the Study:

• To describe the clinical phenotype of genetically confirmed McArdle patients.
• To identify common genetic mutations and their prevalence.

Main Methods:

• Clinical data collection from 45 genetically confirmed McArdle patients.
• Genetic screening for pArg50X (R50X) and pGly205Ser (G205S) mutations.
• Utilized a 12-minute walking test for functional assessment.

Main Results:

• Symptom onset in 84% was in early childhood, with diagnosis often delayed past 30 years.
• Significant functional impairment was observed, with a mean walking distance of 512 meters.
• Muscle hypertrophy occurred in 24%; wasting and weakness were seen in older patients (>40 years).
• pArg50X and pGly205Ser mutations were found in 96% of Caucasian British patients.

Conclusions:

• McArdle disease exhibits a wide spectrum of severity and functional impairment.
• Early childhood onset with delayed diagnosis is common.
• Specific genetic mutations are highly prevalent in Caucasian British patients.