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

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

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

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