X连锁Charcot-Marie-Tooth病1型六个家系的病理和基因突变特点

目的 报道6个X连锁Charcot-Marie-Tooth病1型(CMTX1)家系的神经病理和基因型改变特点.方法 6个CMTX1家系的先证者均为男性,发病年龄11 ～24岁,出现下肢远端为主的肌无力、腱反射减低和轻度感觉减退.先证者1伴随发作性白质脑病,先证者5伴随小脑性共济失调.12名家系成员也出现周围神经损害症状,另7名存在高弓足或腱反射减低.对6例先证者行腓肠神经活体组织检查,并对6例先证者、8名受累家庭成员和10名无症状家系成员及50名健康女性进行缝隙连接蛋白32( Cx32)基因测序.结果 6例先证者有髓神经纤维出现轻-中度减少伴轴索再生变性,5例出现薄髓鞘神经纤维,其中3例伴洋葱球样结构,2例伴炎细胞浸润.6个家系的Cx32基因存在5种新突变和1种同义突变,即L20T、I127F、D178G、A197V错义突变,403_404T insT插入突变和L10L沉默突变,10名无症状家系成员中有4名女性为携带者,6名男性和健康对照均没有这些基因突变.结论 该组CMTX1患者的周围神经病理改变以慢性轴索损害为主,Cx32基因较多新突变的出现提示我国CMTX1患者具有个体突变特点.

Pathologic and genetic features in 6 Chinese X-linked Charcot-Marie-Tooth disease type 1 families

Objectives To report pathological and genetic features of 6 Chinese families with Xlinked Charcot-Marie-Tooth disease type 1 ( CMTX1 ).Methods The index cases from 6 families with CMTX1 are males with onset of disease between 11 and 24 years old.All of them had distal leg muscle weakness,accompanied with areflexia and sensory loss in the feet.Additionally,the index 1 presented with recurrent encephalopathy and the index case 5 with cerebellar ataxia.Peripheral neuropathy was found in 12 family members,while other 7 members showed talipescavus and hyporeflexia.Sural nerve biopsies were performed in all index cases.Connexin 32(Cx32) gene was analyzed in the index cases,8 affected and 10unaffected family members as well as 50 healthy women control subjects.Results Mild to moderate loss of myelinated fiber with axonal degeneration and regeneration clusters were found in all index cases. Thin myelin fibers were found in 5,small onion bulbs in 3 and inflammatory infiltrates in 2.Five novel mutations (I20T,I127F,D178G,A197V,403_404insT) and one L10L synonymous mutation were detected in the 6index cases and their affected family members.The same mutations,in heterozygous state,were detected in 4 female family members without clinical symptoms,but not found in 6 male unaffected family members.The same mutations were not found in healthy control subjects.Conclusions The CMTX1 patients in our study present predominantly axonal lesions.Frequent novel Cx32 gene mutations indicated that private mutations may be common in Chinese CMTX1 patients.