Clinical characteristics and electron transfer flavoprotein dehydrogenase genetic mutations in 26 patients with riboflavin reactive lipid deposition myopathy / 中华神经医学杂志

ABSTRACT

Objective:To investigate the clinical characteristics and electron transfer flavoprotein dehydrogenase ( ETFDH) genetic mutations in patients with riboflavin responsive lipid storage myopathy (RR-LSM). Methods:A retrospective analysis was performed. The clinical data and muscular pathology of 26 patients with RR-LSM, admitted to our hospital from January 2009 to June 2021, were collected. Peripheral venous blood DNA was extracted, and the mutations of ETFDH gene were detected and analyzed by whole exome sequencing. Results:These 26 patients had onset of proximal limb myasthenia, 17 patients had difficulty in raising their head, 12 patients had mastication weakness, 6 had dysphagia, 5 had nausea and vomiting, and one was complicated with rhabdomyolysis and one was with reversible splenic lesion syndrome. Muscle biopsy indicated pathological deposition of lipid droplet, which type I fibers were involved mainly; degenerative necrotic muscle fibers were seen in a few cases. ETFDH gene mutations were detected in 26 patients; 23 patients had compound heterozygous mutation, two had single heterozygous mutation and one had homozygous mutation; 25 different mutation sites were found, mainly missense mutations; the C.770A>G frequency was the highest, accounting for 20% alleles (10/50); two novel mutation sites were found: c.1115A>G and c.1781T>C. Conclusion:RR-LSM is mainly characterized by proximal limb muscle weakness and fatigue intolerance, often accompanied by neck extensor and masticatory weakness; c. 770A>G is the hot site of ETFDH genetic mutations in RR-LSM patients.