SELENON-related myopathy as a cause of acute respiratory failure in middle age: a case report

Background SELENON-related myopathy is a rare autosomal recessive congenital neuromuscular disorder linked to defects in the selenoprotein N. The clinical onset typically occurs in infancy and axial weakness, rigid spine, and respiratory involvement are almost invariably present at early stages. Case presentation We report the case of a 44-year-old Italian woman who underwent intubation for acute respiratory failure, followed by weaning from invasive ventilation within 6 months. Her medical history was not significant, but a detailed medical history collection revealed slight motor limitations since childhood such as slow running, difficulty climbing high steps, early muscle exhaustion, and fatigue.<br /> The neurological examination showed a waddling gait and axial and proximal limb muscle weakness without rigid spine. The right quadriceps muscle biopsy showed nonspecific myopathic abnormalities. Clinical exome sequencing revealed the presence of the two heterozygous variants c.713DupA and c.803G > A in the SELENON gene. Conclusion This report focused on the clinical heterogeneity of SELENON-related myopathy. While we highlight that the absence of spinal rigidity and core pathology on muscle biopsy should not exclude the diagnostic suspicion, overall we stress the importance of respiratory failure as a possible late manifestation of the disease, even in middle-aged individuals.