胶原Ⅵ蛋白相关肌病六例临床、病理、分子生物学研究

Clinical,pathological and molecular biological study of six patients with collagen type Ⅵ related myopathies

目的回顾性分析经分子生物学诊断的6例胶原Ⅵ蛋白相关肌病患者的临床、病理、基因变异特点,提高对胶原Ⅵ蛋白相关肌病的认识.方法对2010—2017年间于我科住院的患者,经外周血或冰冻骨骼肌组织行二代测序后筛选胶原Ⅵ蛋白相关肌病6例,收集患者临床资料、骨骼肌活体组织检查结果等.结果6例患者均为幼儿期起病,起病年龄（2.00±0.75）岁,出生后存在运动发育迟缓;6例均表现为四肢近端肌无力,1例伴远端肌无力;3例伴骨关节病变;1例重度皮肤瘢痕.血清肌酸激酶187-380U/L,呈轻度升高.肌电图3例均呈肌源性改变,2例轻度神经源性改变,1例为肌源性合并神经源性改变.二代测序基因检测结果发现4例COL6A1基因杂合突变（3例为已报,1例新发）、1例COL6A2基因新发杂合突变、1例COL6A1和COL6A2新发复合杂合突变.骨骼肌活体组织检查病理分析示：肌纤维大小不一、结缔组织增生明显,散在不透光肌纤维;6例均经抗胶原Ⅵ、Ⅳ蛋白单克隆抗体免疫荧光双染,肌纤维膜胶原Ⅵ蛋白表达均呈不同程度缺失.结论胶原Ⅵ蛋白相关肌病具有高度临床异质性,骨骼肌活体组织检查病理分析缺少特异性,抗胶原Ⅵ、Ⅳ单克隆抗体免疫荧光双染可见胶原Ⅵ蛋白部分或完全缺失.二代测序基因分析对于诊断临床中间型胶原Ⅵ蛋白相关肌病具有重要价值.

Objective Clinical, pathological and molecular biological data of six cases with molecular diagnosis of collagen type Ⅵ related myopathies were retrospectively analyzed to improve the recognition of collagen protein Ⅵrelated myopathy.Methods Clinical and pathological data of six patients diagnosed as collagen protein Ⅵ related myopathy by next generation sequencing and molecular biologic analysis during 2010-2017 were summarized.Results All of the six patients presented early childhood onset （（2.00 ±0.75） years old）, and delayed motor growth after birth.There were six cases of proximal muscle weakness , one with distal muscle weakness; three cases with osteoarthropathy; one case of severe skin scar.The creatine kinase levels （187-380 U/L） of three patients were slightly elevated .Three cases showed myogenic damage , two with mild neurogenic lesions , one with myogenic and neurogenic damages . Next generation sequencing showed four cases with COL 6A1 gene heterozygous mutation （ a novel mutation and three had been reported）, one with COL6A2 heterozygous mutation and one with COL6A1 and COL6A2 complex heterozygous mutation .The pathological analysis of skeletal muscle biopsy showed that the muscle fiber size was different , and the connective tissue elements were seriously increased .Some opaque fibers were observed.Six cases were found anti-collagen Ⅵ/Ⅳ protein monoclonal antibody immunofluorescence double stained , and sarcolemma Ⅵcollagen protein expression decreased to different degrees .Conclusions The clinical manifestations of the collagen protein Ⅵ related myopathy were found to be complex .Skeletal muscle biopsy pathological analysis was lack of specificity . Anti-collagen Ⅵ/Ⅳ monoclonal antibody immunofluorescence double staining showed collagen protein Ⅵ missing partly or completely . Immunofluorescence staining and the next generation sequencing can improve the diagnosis of collagen proteinⅥrelated myopathy.