Myelin protein zero gene mutations in Taiwanese patients with Charcot–Marie–Tooth disease type 1

Abstract Background : Charcot–Marie–Tooth disease type 1 (CMT1) is the most common inherited peripheral neuropathy and represents a genetically heterogeneous condition. In addition to the peripheral myelin protein 22 gene ( PMP22 ) duplication (CMT1A), myelin protein zero gene ( MPZ ) mutations may account for a certain portion of CMT1 patients (CMT1B). Objectives : The authors analyzed the MPZ mutations in Taiwanese patients who do not have PMP22 duplication. Specifically, their clinical and molecular features were characterized. Materials and methods : Twenty-four of 57 unrelated Taiwanese patients with CMT1 were selected after excluding the CMT1A duplication. Subsequent analysis of the coding regions of the MPZ gene was performed with single-strand-conformation polymorphism (SSCP), which was then followed by nucleotide sequencing. Results : Four missense mutations and one 4-base pair (bp) deletion, respectively, were identified in five patients, of which one mutation, c.173 T>A, has never been previously reported. Three missense mutations were located in exon 2, the other one in exon 3, and the deletion in exon 6. Conclusions : This study expands the number of CMT1 associated MPZ mutation and suggests that analysis of the coding sequence of MPZ should be performed in all CMT patients without CMT1A duplication to clarify their disease nature.