A study of 22 cases of lipid storage myopathy involving clinical-pathological analysis and differential diagnosis

KE Zhen-yu; KANG Juan; ZHANG Wei-chen; WANG Ying-mei; ZHANG Qian; WU Jun-feng; LIU Jian; LI Qing; XU Yu-qiao

doi:10.3969/j.issn.1007-8096.2025.05.004

Abstract：Objective This study aims to provide a comprehensive summary of the clinical,pathological,and molecular features of lipid storage myopathy,discuss its diagnosis and differential diagnosis to enhance knowledge of the disease.Methods Twenty-two cases of lipid storage diseases treated in xijing hospital between 2010 and 2023 were collected.Clinical manifestations,auxiliary examinations,histological observations,special staining,electron microscopy observations,and genetic results of this group of cases were analyzed.Results There were 11 male and 11 female patients,with a median age of 26 years and a median disease duration of 6.5 months.The primary clinical symptoms included recurring or worsening limb weakness,along with challenges in squatting and standing up.Muscle electromyography showed myogenic damage in 16 cases.Laboratory tests showed elevated levels of creatine kinase,lactate dehydrogenase,and blood lactate concentration.Morphological observations:Under the light microscope,muscle fibers in this group of cases showed varying degrees of thickness,with oil red O staining revealing abundant lipid droplet deposition in the cytoplasm,mainly in type I muscle fibers.The electron microscopy results revealed a notable rise in lipid droplets congregated in strings or clusters within muscle fibers,accompanied by an increase in mitochondria and glycogen granules,as well as a slight proliferation and expansion of the sarcoplasmic reticulum.Genetic testing results:Seven cases underwent genetic testing,all of which detected mutations in the ETFDH gene,leading to abnormal mitochondrial oxidative respiratory chain function and fatty acid metabolism disorders,resulting in lipid accumulation,consistent with multiple acyl-CoA dehydrogenase deficiency(MADD).Conclusion Most cases of lipid storage disease in China are MADD,and the diagnosis needs to be differentiated from other diseases that cause increased lipid droplets in muscle fibers,such as muscular dystrophy,inflammatory myopathy,and mitochondrial myopathy.