Pathologic and genetic features in 6 Chinese X-linked Charcot-Marie-Tooth disease type 1 families / 中华神经科杂志

ABSTRACT

ObjectivesTo 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.ResultsMild 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.ConclusionsThe 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.