Objective To study the clinical,pathological and genetic features of myofibrillar myopathy caused by BAG3 gene mutation.Methods The clinical features and pathological findings of a patient with myofibrillar myopathy were analyzed.Genomic DNA of the patient was extracted from peripheral blood and the next generation sequencing was performed to explore the mutation of genes about myopathies.Results The patient presented with nine-year-old onset myopathy characterized by progressive difficulty for squatting,rigid spine and muscle atrophy in the limbs symmetrically.Peripheral neurogenic damages were found on electromyography.On muscle biopsy,myogenic and neurogenic damages with rimmed vacuoles appeared,and the deposited materials were positive for sarcoglycan,dystrophin-R and dystrophin-C.There was a reported heterozygous mutation in the exons of the BAG3 gene (c.626C ＞ T).Conclusion There is no specificity of clinical manifestation in myofibrillar myopathy,and the diagnosis of this disease mainly depends on muscle biopsy and genetic screening.

BACKGROUND:Previous studies have shown that kainic acid injected into hippocampus can significantly upregulate the expression of excitatory KA1 subunit of the kainate receptor in the hippocampus, and endoplasmic reticulum stress markers, phosphorylation of the alpha subunit of eukaryotic initiation factor 2, accompanied by celldeath. OBJECTIVE:To explore the mechanism of endoplasmic reticulum stress after kainic acid is injected into the hippocampus.METHODS:0.15 nmol kainic acid was injected into the hippocampal CA1 region of 32 adult male Kunming mice, the injection time was 60 seconds. At different time points (1, 2, 3, 4, 5, 6, 8 and 12 hours) after kainic acid was injected, the Bederson score analysis was performed, and then the brain was harvested after cerebral perfusion. FJB staining of brain sections and immunofluorescence double labeled observation were also performed. RESULTS AND CONCLUSION:(1) At 3, 4, 5, 6, 8 hours after kainic acid injection, Bederson score showed severe injury of central nervous system function, and FJB staining showed the increased of celldeath in the hippocampus (P<0.05);At 1, 2, 12 hours after injection, Bederson score showed no obvious injury of central nervous system function, and FJB staining showed unobvious celldeath in the hippocampus (P>0.05). (2) According to the results of FJB staining, the brain sections were selected at 3, 8 hours for immunohistochemistry. The expressionlevels of KA1 receptors and endoplasmic reticulum stress marker P-eIF2αwere up-regulated at the same time after kainic acid was injected into hippocampus. Two single-staining KA1 and P-eIF2αimmunofluorescence images were synthesized into one over-lapped double-stained image, and two images overlapped, indicating that the up-regulated expression of KA1 and endoplasmic reticulum stress occurred in the same nerve cells. Kainic acid first up-regulated the excitatory receptor KA1 expression, which may cause cellendoplasmic reticulum dysfunction and result in the endoplasmic reticulum stress response, further promoting neuronal celldeath.