目的 报道1例Danon病患者的临床表现、病理改变特点和基因突变位点.方法 16岁男性患者表现为缓慢进展的骨骼肌无力和萎缩,以近端为主,伴随轻度脊柱强直.心电图示Ⅰ度房室传导阻滞,心脏超声示二尖瓣局限性增厚伴舒张功能损害,肌电图提示神经源性合并肌源性损害.患者左腓肠肌活体组织检查后,进行组织学、酶组织化学、电镜观察及抗肌营养不良素蛋白、层黏连蛋白α2、C5b9等免疫组织化学染色.患者及其父母进行溶酶体相关膜蛋白2(LAMP2)B基因的直接测序.结果 骨骼肌纤维内出现大小不一的自嗜空泡和镶边空泡,空泡内缺乏糖原,免疫组织化学显示多数肌纤维内的空泡边缘出现肌营养不良素蛋白、层黏连蛋白α2和C5b9的表达.电镜显示肌纤维内大量膜性空泡和溶酶体聚集.患者的LAMP2B基因9号外显子存在K402X突变,患者母亲无此突变,50名健康对照无此突变.结论 LAMP2B的9号外显子羧基末端的截断突变可以导致相对良性的Danon病,其心脏损害相对轻微.%Objectives To report the clinical and myopathological features in a case with Danon disease caused by a novel mutation in the lysosome-associated membrane protein-2 ( LAMP2 ) B gene.Methods A 16-year-old boy presenting progressive muscle weakness and atrophy, accompanied with spinal ankylosis was clinically evaluated including electrocardiogram, echocardiogram and electromyogram.Muscle biopsy was carried out in the patient.The histological staining, ultrastructural examination, and immunohistochemical staining with antibodies against dystrophin, merosin and C5b9 were performed in frozen sections.LAMP2B sequence was analyzed in the patient and his parents.Results Electrocardiogram in the patient showed Ⅰ atrioventricular block; echocardiogram revealed focal hypertrophy in mitral valve with mild cardiac diastolic dysfunction; electromyogram indicated myogenic and neurogenic patterns.Muscle pathology study revealed numerous vacuoles located at the fibers.Dystrophin, merosin and C5b9 was immuno-positive around the vacuoles.Electron microscopy revealed vacuoles surrounded by sarcolemma and abnormal lysosome aggregating at the fibers.A novel nonsense mutation ( K402X ) in the LAMP2B gene has been identified in the patient but not in his mother and 50 normal controls.Conclusions Danon disease caused by K402X mutation in C-terminus of LAMP2B presented benign course of the disease characterized by prominent vacuolar skeletal myopathy, mild cardiac abnormalities and peripheral neuropathy.
展开▼
