眼咽型肌营养不良一家系临床、电生理、病理及基因分析

目的 报道1个出现神经源性骨骼肌损害的眼咽型肌营养不良(OPMD)家系的临床、骨骼肌病理和基因改变特点.方法 先证者为60岁男性,50岁时出现双下肢近端无力,53岁出现吞咽困难和构音障碍,57岁出现双眼睑下垂和眼球突出.肌酸激酶轻度增加,四肢肌电图为神经源性损伤,周围神经传导速度下降20%～43%.家系3代中除先证者外尚有5例在45岁后出现吞咽困难,4～20年后出现眼睑下垂,其中3例有肢体无力.对先证者左肱二头肌做肌肉活体组织检查,标本进行组织学、酶组织化学以及免疫组织化学染色(以抗结蛋白和泛素蛋白抗体作为一抗)和超微病理检查.对先证者和家系中另外18人进行多腺苷酸结合蛋白(PABPN1)基因检查.结果 先证者肌纤维内出现镶边空泡伴泛素阳性沉积物和成组分布的小角状萎缩肌纤维,个别肌纤维出现再生改变伴随结蛋白沉积,可见细胞色素C氧化酶阴性肌纤维.电镜检查发现约3%的肌纤维核内存在栅栏样细丝包涵体.先证者和另外11名家系成员的PABPN1基因存在(GCG)9异常扩增.结论 杂合(GCG).异常扩增性OPMD可先出现咽喉肌无力,伴随脱髓鞘性神经病.我国患者也存在肌纤维核内包涵体.

Oculopharyngeal muscular dystrophy,the clinical,electrophysiologic,myopathological and genetic study in a family

Objective To report clinical,myopathological and genetic features in a family with oculopharyngeal muscular dystrophy(OPMD).Methods The proband,a 60 year-old man,presented proximal weakness of both lower limbs since 50 years old.He developed dysphagia and dysarthria after 53 years old and mild exophthalmos with ptosis after 57 years old.The serum creatine kinase was mildly elevated.Electromyography showed neurogenic involvement and the nerve conduction velocity decreased 20%-143%.Other 5 members in 3 generations developed also dysathria after 45 years old.followed by ptosis 4-20 years afterwards.Three of them showed mild limb weakness.Muscle was biopsied in the proband and specimen was examined with histological,enzymhistochemical,immunohistochemical stainings (first antibody were anti.desmin and ubiquitin antibedies) and ultrastructural examination.PABPN1 gene was sequenced in the proband and 18 family members.Results Rimmed vacuoles with ubiquitin positive material appeared in the muscle fibers.Additionally.there were a few angular atrophic fibers in small groups,COX negative fibers and desmin positive regenerative fibers.Intranuclear palisading filamentous inclusions were observed electromicroscopically in 3% of the nuclears.(GCG)6in PABPN1 was expanded to (GCG)9 in the proband and 11 members.Conclusions The onset symptoms is pharyngeal weakness in OPMD due to heterozygous expanding of PABPNl(GCG)9,accompanied with demyelinating neuropathy.Intranuclear inclusions are also identified in Chinese patient.