Congenital myopathy presenting as recurrent pneumonia with lung collapse and pulmonary artery hypertension

Area of Science:

• Neurology
• Genetics
• Pediatrics

Background:

• Congenital myopathies (CM) are a group of rare neuromuscular disorders affecting muscle development.
• SEPN1-related myopathy, caused by mutations in the SELENON gene, is characterized by fiber-type disproportion.
• Respiratory involvement is a common and serious complication in congenital myopathies.

Observation:

• A boy presented with persistent respiratory distress, fever, and failure to thrive, initially diagnosed as recurrent pneumonia.
• Despite ventilation and nutritional support, muscle wasting and myopathic facies were noted.
• Pulmonary arterial hypertension and recurrent lung collapse were observed, complicating the initial diagnosis.

Findings:

• Genetic analysis revealed a frameshift duplication in the SELENON gene (NM_020451.3:c.249_250dupGG), confirming SEPN1-related congenital myopathy with fiber-type disproportion.
• Normal creatine kinase levels and negative workups for cystic fibrosis and immunodeficiency highlighted the need for genetic testing.
• Reduced fetal movements and low voice amplitude were key historical clues.

Implications:

• This case underscores that SEPN1-related congenital myopathy can manifest primarily with severe respiratory symptoms, potentially masking the underlying neuromuscular condition.
• It emphasizes the importance of considering congenital myopathies in pediatric patients with unexplained respiratory failure, muscle wasting, and failure to thrive.
• Timely genetic diagnosis is critical for appropriate management and counseling in SEPN1-related congenital myopathy.