OBJECTIVE: Distal hereditary motor neuropathy (dHMN) comprises a heterogeneous group of inherited disorders associated with neurodegeneration of motor nerves and neurons, mainly charac-terized by progressive atrophy and weakness of distal muscle without clinical or electrophysiological sensory abnormalities. To improve the recognition and diagnosis of the disease, we summarized the clinical manifestations, electrophysiological, pathological, and genetic characteristics in eight patients with dHMN. METHODS: Eight probands from different families diagnosed with dHMN were recruited in this study between June 2018 and April 2019 at Peking University People's Hospital. Eight patients underwent complete neurological examination and standard electrophysiological examinations. The clinical criteria were consistent with the patients presenting with a pure motor neuropathy with no sensory changes on electrophysiology. The detailed clinical symptoms, neurophysiological examinations, pathological features and gene mutations were analyzed retrospectively. Genetic testing was performed on the eight patients using targeted next-generation sequencing panel for inherited neuromuscular disorder and was combined with segregation analysis. RESULTS: The age of onset ranged between 11 and 64 years (median 39.5 years) in our dHMN patients. All the cases showed a slowly progressive disease course, mainly characterized by distal limb muscle weakness and atrophy. The motor nerve conduction revealed decreased compound muscle action potential amplitude and velocity, while the sensory nerve conduction velocities and action potentials were not affected. Needle electromyography indicated neurogenic chronic denervation in all patients. Muscle biopsy performed in two patients demonstrated neurogenic skeletal muscle damage. Sural nerve biopsy was performed in one patient, Semithin sections shows relatively normal density and structure of large myelinated fibers, except very few fibers with thin myelin sheaths, which suggested very mild sensory nerve involvement. Eight different genes known to be associated with dHMN were identified in the patients by next-generation sequencing, pathogenic dHMN mutations were identified in three genes, and the detection rate of confirmed genetic diagnosis of dHMN was 37.5% (3/8). Whereas five variants of uncertain significance (VUS) were identified, among which two novel variants co-segregated the phenotype. CONCLUSION dHMN is a group of inherited peripheral neuropathies with great clinical and genetic heterogeneity. Next-generation sequencing is widely used to discover pathogenic genes in patients with dHMN, but more than half of the patients still remain genetically unknown.
Adolescent ; Adult ; Child ; Hereditary Sensory and Motor Neuropathy/genetics* ; Humans ; Middle Aged ; Mutation ; Peripheral Nervous System Diseases ; Phenotype ; Retrospective Studies ; Young Adult

Child ; Female ; Hereditary Sensory and Motor Neuropathy ; genetics ; Heterozygote ; Humans ; Mitochondrial Proteins ; genetics ; Mutation ; genetics ; Optic Atrophy ; genetics ; Peptide Termination Factors ; genetics

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

BACKGROUND: Mutations in the gene encoding periaxin (PRX) are known to cause autosomal recessive Dejerine-Sottas neuropathy (DSN) or Charcot-Marie-Tooth disease type 4F. However, there have been no reports describing Korean patients with these mutations. CASE REPORT: We examined a Korean DSN patient with an early-onset, slowly progressive, demyelinating neuropathy with prominent sensory involvement. Whole-exome sequencing and subsequent capillary sequencing revealed novel compound heterozygous nonsense mutations (p.R392X and p.R679X) in PRX. One mutation was transmitted from each of the patient's parents. No unaffected family member had both mutations, and the mutations were not found in healthy controls. CONCLUSIONS: We believe that these novel compound heterozygous nonsense mutations are the underlying cause of DSN. The clinical, electrophysiologic, and pathologic phenotypes in this family were similar to those described previously for patients with PRX mutations. We have identified the first PRX mutation in a Korean patient with DSN.
Capillaries ; Charcot-Marie-Tooth Disease ; Codon, Nonsense ; Hereditary Sensory and Motor Neuropathy* ; Humans ; Parents ; Peripheral Nerves ; Phenotype

Compared with biochemical information available about the diseases in the central nervous system, that for peripheral neuropathy is quite limited primarily due to the difficulties in obtaining samples. Characterization of the core pathology is a prerequisite to the development of personalized medicine for genetically heterogeneous diseases, such as hereditary motor and sensory neuropathy (HMSN). Here, we first documented the transcriptome profile of distal sural nerve obtained from HMSN patients. RNA-seq analysis revealed that over 12,000 genes are expressed in distal sural nerve. Among them 4,000 transcripts are novel and 10 fusion genes per sample were observed. Comparing dataset from whole exome sequencing revealed that over 1,500 transcriptional base modifications occur during transcription. These data implicate that dynamic alterations are generated when genetic information are transitioned in distal sural nerve. Although, we could not find significant alterations associated with HMSN, these data might provide crucial information about the pathophysiology of HMSN. Therefore, next step in the development of therapeutic strategy for HMSN might be unveiling biochemical and biophysical abnormalities derived from those potent variation.
Central Nervous System ; Dataset ; Exome ; Gene Expression Profiling* ; Hereditary Sensory and Motor Neuropathy ; Humans ; Pathology ; Peripheral Nervous System Diseases ; Sural Nerve* ; Transcriptome ; Precision Medicine

Charcot-Marie-Tooth disease (CMT) 2A with optic atrophy is referred to as hereditary motor and sensory neuropathy type VI (HMSN VI) and is caused by mitofusin 2 gene (MFN2) mutation. In patients with MFN2 related CMT, central nervous system is known to be also involved and cerebral white matter is mostly involved. We report a patient confirmed as HMSN VI who had isolated bilateral middle cerebellar peduncular lesions in brain MRI.
Brain ; Central Nervous System ; Charcot-Marie-Tooth Disease ; Hereditary Sensory and Motor Neuropathy* ; Humans ; Magnetic Resonance Imaging ; Mitochondria ; Optic Atrophy

Adult ; Aged ; Female ; Hereditary Sensory and Motor Neuropathy ; diagnosis ; genetics ; Humans ; Male ; Middle Aged ; Pedigree

Adult ; Aged ; Arthrogryposis ; diagnosis ; Female ; Hereditary Sensory and Motor Neuropathy ; diagnosis ; Humans ; Male ; Middle Aged ; Pedigree ; Young Adult

Hereditary peripheral neuropathies can be categorized as hereditary motor and sensory neuropathies (HMSN), hereditary motor neuropathies (HMN), and hereditary sensory neuropathies (HSN). HMSN, HMN, and HSN are further subdivided into several subtypes. Here, we review the most recent findings in the molecular diagnosis and therapeutic strategy for hereditary peripheral neuropathies. The products of genes associated with hereditary peripheral neuropathy phenotypes are important for neuronal structure maintenance, axonal transport, nerve signal transduction, and functions related to the cellular integrity. Identifying the molecular basis of hereditary peripheral neuropathy and studying the relevant genes and their functions is important to understand the pathophysiological mechanisms of these neurodegenerative disorders, as well as the processes involved in the normal development and function of the peripheral nervous system. These advances and the better understanding of the pathogenesis of peripheral neuropathies represent a challenge for the diagnoses and managements of hereditary peripheral neuropathy patients in developing future supportive and curative therapies.
Axonal Transport ; Hereditary Sensory and Autonomic Neuropathies ; Hereditary Sensory and Motor Neuropathy ; Humans ; Neurodegenerative Diseases ; Neurons ; Peripheral Nervous System ; Peripheral Nervous System Diseases ; Phenotype ; Signal Transduction ; Wills

Charcot-Marie-Tooth disease, which is also known as hereditary motor and sensory neuropathy, is a heterogenous group of inherited diseases of the peripheral nerve. The spectrum of severity varies from asymptomatic individuals to those with severe limb abnormalities requiring corrective surgery. We report two brothers who had previously been diagnosed with Charcot-Marie- Tooth disease 3 years earlier and were scheduled to undergo a correction osteotomy of both feet under general anesthesia. General anesthesia was induced with propofol 2 mg/kg, rocuronium 0.8 mg/kg and was maintained with O2-N2O-Sevoflurane. The younger brother showed no delay in recovery of the neuromuscular blockade but the elder brother showed a delay.
Anesthesia, General ; Charcot-Marie-Tooth Disease* ; Extremities ; Foot ; Hereditary Sensory and Motor Neuropathy ; Humans ; Neuromuscular Blockade* ; Osteotomy ; Peripheral Nerves ; Propofol ; Siblings ; Tooth Diseases