OBJECTIVETo study the electromyographic and genetic characteristics in children with Charcot-Marie-Tooth disease type 1 (CMT1).

METHODSRoutine electromyography and nerve conduction were performed in 24 children with CMT1. Polymerase chain reaction (PCR) combined with restriction enzyme digestion was used to detect gene duplication on chromosome 17p11.2-12. Ten healthy children served as the control group.

RESULTSThe peripheral nerve conduction velocity slowed or disappeared in all of the 24 patients (100%). The lesions of the sensory nerves were more severe than the motor nerves, and the lesions of the lower limbs were more severe than the upper limbs. Of 72 muscles detected, 40 (56%) showed neurogenic lesions. The older the patients, the more severe the muscle lesions. Specific junction fragments (1760 bp) were identified in 13 (54%) out of 24 patients, but were not identified in the healthy controls.

CONCLUSIONSThe electromyographic changes are characterized by peripheral nerve conduction velocities slowing and neurogenic lesions of muscles in children with CMT1. The PCR combined with restriction enzyme digestion may be a simple and accurate method for gene diagnosis of CMT1.

Adolescent ; Charcot-Marie-Tooth Disease ; genetics ; physiopathology ; Child ; Electromyography ; Female ; Humans ; Male ; Neural Conduction

OBJECTIVETo delineate the clinical, electrophysiological and genetics features of a family where 4 members were affected with hereditary neuropathy with liability to pressure palsies (HNPP).

METHODSClinical features of the 4 patients were summarized. Electrophysiological examination and genetic analysis were carried out.

RESULTSAll of the patients showed recurrent motor and sensory disturbances after minor traction or constriction. Electrophysiology study revealed that the prolonged latency and reduced conduction velocity of peripheral nerve were general and with multiple sites of affection. The nerve locations liable to entrapment showed conduction block. A deletion mutation of peripheral myelin protein 22 (PMP22) gene was identified by genetic analysis.

CONCLUSIONHNPP usually affects areas where nerves are liable to entrapment, and presents with motor and sensory disturbances of the innervated areas. Electrophysiological study reveals general nervous demyelination. Genetic analysis can clarify the diagnosis of HNPP.

Adult ; Arthrogryposis ; genetics ; physiopathology ; Hereditary Sensory and Motor Neuropathy ; genetics ; physiopathology ; Humans ; Male ; Myelin Proteins ; genetics ; Neural Conduction

BACKGROUNDAmong patients with Charcot-Marie-Tooth disease (CMT), the X-linked variant (CMTX) caused by gap junction protein beta 1 (GJB1) gene mutation is the second most frequent type, accounting for approximately 90% of all CMTX. More than 400 mutations have been identified in the GJB1 gene that encodes connexin 32 (CX32). CX32 is thought to form gap junctions that promote the diffusion pathway between cells. GJB1 mutations interfere with the formation of the functional channel and impair the maintenance of peripheral myelin, and novel mutations are continually discovered.

METHODSWe included 79 unrelated patients clinically diagnosed with CMT at the Department of Neurology of the Chinese People's Liberation Army General Hospital from December 20, 2012, to December 31, 2015. Clinical examination, nerve conduction studies, and molecular and bioinformatics analyses were performed to identify patients with CMTX1.

RESULTSNine GJB1 mutations (c.283G>A, c.77C>T, c.643C>T, c.515C>T, c.191G>A, c.610C>T, c.490C>T, c.491G>A, and c.44G>A) were discovered in nine patients. Median motor nerve conduction velocities of all nine patients were < 38 m/s, resembling CMT Type 1. Three novel mutations, c.643C>T, c.191G>A, and c.610C>T, were revealed and bioinformatics analyses indicated high pathogenicity.

CONCLUSIONSThe three novel missense mutations within the GJB1 gene broaden the mutational diversity of CMT1X. Molecular analysis of family members and bioinformatics analyses of the afflicted patients confirmed the pathogenicity of these mutations.

Adolescent ; Adult ; Charcot-Marie-Tooth Disease ; genetics ; physiopathology ; Computational Biology ; Connexins ; genetics ; Female ; Genotype ; Humans ; Male ; Middle Aged ; Mutation, Missense ; Neural Conduction ; Phenotype

Distal hereditary motor neuropathy (dHMN) is a heterogeneous disorder characterized by degeneration of motor nerves in the absence of sensory abnormalities. Recently, mutations in the small heat shock protein 27 (HSP27) gene were found to cause dHMN type II or Charcot-Marie-Tooth disease type 2F (CMT2F). The authors studied 151 Korean axonal CMT or dHMN families, and found a large Korean dHMN type II family with the Ser135Phe mutation in HSP27. This mutation was inherited in an autosomal dominant manner, and was well associated with familial members with the dHMN phenotype. This mutation site is located in the ?-crystallin domain and is highly conserved between different species. The frequency of this HSP27 mutation in Koreans was 0.6%. Magnetic resonance imaging analysis revealed that fatty infiltrations tended to progressively extend distal to proximal muscles in lower extremities. In addition, fatty infiltrations in thigh muscles progressed to affect posterior and anterior compartments but to lesser extents in medial compartment, which differs from CMT1A patients presenting with severe involvements of posterior and medial compartments but less involvement of anterior compartment. The authors describe the clinical and neuroimaging findings of the first Korean dHMN patients with the HSP27 Ser135Phe mutation. To our knowledge, this is the first report of the neuroimaging findings of dHMN type II.
Adolescent ; Adult ; Age of Onset ; Animals ; Asian Continental Ancestry Group ; Charcot-Marie-Tooth Disease/*genetics/physiopathology/radionuclide imaging ; Child ; Child, Preschool ; Female ; *Genetic Predisposition to Disease ; Humans ; Intracellular Signaling Peptides and Proteins/*genetics ; Korea ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Muscular Atrophy/physiopathology/radionuclide imaging ; *Mutation, Missense ; Neural Conduction/genetics ; Pedigree ; Protein-Serine-Threonine Kinases/*genetics ; alpha-Crystallins/genetics