Clinical, pathological and genetic characteristics of 8 patients with distal hereditary motor neuropathy / 北京大学学报(医学版)

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.

Co-existence of Guillain-Barré syndrome and Behcet syndrome: A case report / 北京大学学报(医学版)

A 40-year-old male patient was referred to our department with complains of recurrent oral ulcer for more than 20 years and vulvar ulcer for more than 10 years. He presented with a 3-month history of right external ophthalmoplegia. More than 10 days ago, the patient received ganglioside infusion. And one week ago, he developed numbness and pain of his lambs, and progressive myasthenia, accompanied by right blepharoptosis and dysuria. On exam, motor strength was graded 0/5 in the lower and the upper extremities. Deep tendon reflexes were diminished in extremities. His admission medical examination: hemoglobin (HGB), white cell and platelet counts were normal. C-reactive protein (CRP) was negative. Erythrocyte sedimentation rate (ESR) 53 mm/h. Antinuclear antibody (ANA), anti-dsDNA antibody, anti-Smith antibody, anti-cardiolipin antibody and human leucocyte antigen B51 were all within normal range. The etiological tests of influenza A pathogen, influenza B pathogen, parainfluenza virus, enterovirus and parvovirus were all negative. He tested positive for serum anti-GM1 IgG. Cerebrospinal fluid had a normal white cell count, an elevated protein content. Gram staining, culture and PCR detection for varicella-zoster virus, cytomegalovirus and herpes simplex virus were all negative. Antibodies associated with autoimmune encephalitis and paraneoplastic syndrome were negative in cerebrospinal fluid. Electromyography and nerve conduction studies showed a severe axonal damage affecting motor nerves. No obvious abnormalities were observed in his magnetic resonance imaging of brain and cavernous sinus. The patient was diagnosed with Behcet syndrome complicated with acute Guillain-Barré syndrome. He received intravenous methylprednisolone, intravenous immunoglobulin (IVIg) therapy, plasma exchange and rituximab treatment. After treatment, the patient's muscle strength of limbs was restored to grade 1, blepharoptosis and pain disappeared. The nervous system involvement of Behcet syndrome is relatively rare, especially combined with Guillain-Barré syndrome, which is easy to cause misdiagnosis. The treatment of Behcet syndrome complicated with acute Guillain-Barré syndrome includes the treatment of primary disease, plasma exchange and IVIg therapy. In addition, supportive treatment is very important for such patients. The focus of treatment is to avoid respiratory insufficiency, prevent deep vein thrombosis, monitor cardiac function and hemodynamics. Pain-relieving, physical exercise and psychological support are often under-recognized. The rehabilitation treatment is very important to improve the prognosis and quality of life of patients. What we need to learn is that when the symptoms and signs of the nervous system are difficult to be explained by neuro-Behcet syndrome alone, we should be alert to the possibility of other nervous system diseases.