Inherited myopathy plus: Double-trouble from rare neuromuscular disorders

Area of Science:

• Neurology
• Genetics
• Rare Diseases

Background:

• Inherited myopathies are rare diseases, often diagnosed through genetic testing.
• Genetic findings in myopathies necessitate clinical correlation due to variable phenotypes and complex etiologies.
• Co-existing independent neuromuscular disorders can complicate diagnosis and management.

Purpose of the Study:

• To identify and characterize adult patients with inherited myopathies and co-existing rare neuromuscular disorders.
• To emphasize the clinical significance of correlating genetic diagnoses with patient phenotypes.

Main Methods:

• Retrospective search of medical records (2004-2020) at Mayo Clinic Rochester and Nationwide Children's Hospital.
• Inclusion criteria: pathogenic/likely pathogenic variants in myopathy-causative genes and a co-existing rare neuromuscular disorder.
• Review of clinical and laboratory findings for identified patients.

Main Results:

• Fourteen patients from 13 families met the criteria.
• Identified cases included "double-trouble" inherited myopathies, myopathy with idiopathic myositis, and myopathy with rare neurogenic disorders.
• Specific cases involved a DMD carrier with distal spinal muscular atrophy and a MYH7 variant patient with Sandhoff disease.

Conclusions:

• Genetic findings in inherited myopathies require careful clinical correlation for precise diagnosis.
• Accurate diagnosis is crucial for optimal patient care and prognosis in complex neuromuscular cases.
• This study underscores the importance of a holistic diagnostic approach integrating genetic and clinical data.