结蛋白基因突变相关性心肌病五家系临床和遗传特点

目的 研究中国人群结蛋白病的临床表现、肌肉病理改变和基因突变规律.方法 5个家系共36例患者,男18例,女18例.其中心肌病伴骨骼肌病19例,单纯心肌病13例,单纯骨骼肌病1例,3例死于心脏病变但生前临床不详.23例心电图检查中20例伴随多种类型的心脏传导阻滞.23例心脏超声检查发现限制型心肌病2例,扩张型心肌病和肥厚型心肌病各1例.对7例患者行骨骼肌活检,标本行常规组织学、酶组织化学、免疫组织化学和电镜检查.对21例患者、17例无症状家系成员和50名正常中国人行结蛋白基因测序.结果 肌肉活检均提示肌纤维内出现小球形或无定形的嗜酸性物质沉积,免疫组织化学染色显示存在结蛋白沉积,伴随个别肌纤维出现肌营养不良素、分层蛋白和α-辅肌动蛋白的异常聚集.电镜显示肌纤维膜下和肌原纤维之间出现大量颗粒细丝物质.在5个家系发现结蛋白存在5种新的杂合突变.所有突变只出现在患病成员,而正常家系成员及50名正常中国人中没有检测到相同突变.结论 在我国结蛋白基因多种新突变导致的结蛋白病多以不同形式的心肌病为主,特别是心律紊乱相关的心肌病,可以伴随不同程度的骨骼肌损害.

Clinical characteristics and desmin mutations in patients with desminopathy associated cardiomyopathy from 5 Chinese families

Objective To investigate the clinical and myopathological characteristics and desmin mutations in patients with desminopathy associated cardiomyopathy from 5 Chinese families. Methods Thirty-six individuals (18 male, 18 female) were from 4 autosomal dominant inherited families and 1 sporadic case. Nineteen patients manifested myopathy followed by cardiomyopathy; 13 patients presented with isolated cardiomyopathy; 1 patient had isolated myopathy; 3 patients died of cardiac diseases without detailed clinical information. Out of the 23 patients underwent electrocardiogram examinations, 20 patients showed kinds of abnormalities in cardiac conduction block. Echocardiogram revealed dilated cardiomyopahty in one case, hypertrophic cardiomyopathy in one case, and restrictive cardiomyopathy in two cases. Muscle specimens from 7 different patients were performed for histological, immunohistochemistry and ultrastructural examinations. All exons of the desmin gene were screened in 21 patients, 17 asymptomatic family individuals and 50 Chinese controls. Results Muscle biopsies revealed multiple proteins aggregated in muscle fibers, also supported by immunostaining and electroscopic examinations. Five novel heterogeneous mutations were identified in 4 families and one sporadic case. Conclusions Novel mutations of desmin gene were linked with cardiomyopathy in patients from 5 Chinese families with desminopathy.