Analysis of a Chinese family with distal hereditary motor neuropathy type V / 中华神经科杂志

ABSTRACT

Objective:To report the clinical, electrophysiological and genetic features in a Chinese family with distal hereditary motor neuropathy type V (dHMN-V) and screen the pathogenic mutant gene.Methods:A family with the history of inherited peripheral neuropathy was recruited in the First Affiliated Hospital of Zhengzhou University in July 2017. The clinical features and electrophysiological data were investigated. Genetic testing on well-established genes associated with hereditary peripheral neuropathy was conducted by targeted high throughput sequencing and the candidate variant was screened in the family and normal controls.Results:There were four affected individuals in the family. The proband, a 25-year-old male, was characterized by weakness and atrophy in the distal extremities primarily affected the upper extremities without sensory impairment. Electrophysiological study showed chronic neurogenic pattern in the upper and lower limb muscles. The motor conduction showed reduced velocity and compound muscle action potential amplitude, while the sensory conduction studies results were normal. The grandfather, a maternal uncle and a cousin of the proband exhibited similar clinical manifestations and electrophysiological abnormality. Genetic testing revealed a heterozygous mutation, c.880G>A(p.G294R), in the GARS gene in the proband. Proband′s mother and two other affected individuals carried the mutation which was confirmed by Sanger sequencing. The mutation site was not found in the unaffected members from the family and 300 unrelated normal controls. The variant is a novel mutation which has not been reported in dbSNP, ExAC and 1000 Genomes Project databases. Conclusion:The results suggest that the novel c.880G>A(p.G294R) mutation of the GARS gene is responsible for the Chinese patients with dHMN-V, and the findings broaden the mutational spectrum of GARS gene.