Thought ripples on muscle waves: recognition of rippling muscle disease

Area of Science:

• Neurology
• Genetics
• Rare Diseases

Background:

• Misdiagnosis of neuromuscular disorders can delay appropriate treatment and genetic counseling.
• Acid maltase deficiency and rippling muscle disease (RMD) share some overlapping symptoms, complicating differential diagnosis.
• Autosomal dominant inheritance patterns are crucial for accurate diagnosis of genetic neuromuscular conditions.

Observation:

• A 16-year-old Dutch patient presented with symptoms suggestive of RMD.
• The patient's mother had a prior misdiagnosis of acid maltase deficiency.
• Key RMD clinical signs observed included rippling, mounding, and percussion-induced muscle contractions.

Findings:

• Genetic analysis identified a novel heterozygous missense mutation (c.79C > G; p.Arg27Gly) in the caveolin-3 gene in both patient and mother.
• This mutation confirmed the diagnosis of RMD and explained the autosomal dominant inheritance pattern.
• The findings highlight a specific genetic cause for RMD in this family.

Implications:

• Accurate diagnosis of RMD requires recognizing specific clinical signs and considering inheritance patterns.
• This case underscores the importance of re-evaluating previous diagnoses when new genetic information or symptoms emerge.
• Improved awareness of RMD's clinical characteristics among healthcare professionals is needed for timely diagnosis.