Hereditary motor neuropathies

Distal hereditary motor neuropathies (dHMN) are a clinically and genetically diverse group of disorders that are characterized by length-dependent axonal degeneration of lower motor neurons. In this review, we will provide an overview of dHMN, and we will correlate the distinct clinical subtypes with their causative genes, focusing on the most recent advances in the field.

Despite the massive use of new-generation sequencing (NGS) and the discovery of new genes, only a third of dHMN patients receive a molecular diagnosis. Thanks to international cooperation between researchers, new genes have been implicated in dHMN, such as SORD and VWA1 . Mutations in SORD are the most frequent cause of autosomal recessive forms of dHMN. As a result of these findings, the potential benefits of some pharmacological compounds are being studied in cell and animal models, mainly targeting axonal transport and metabolic pathways.

Despite the wide use of NGS, the diagnosis of dHMN remains a challenge. The low prevalence of dHMN makes international cooperation necessary in order to discover new genes and causal mechanisms. Genetic diagnosis of patients and identification of new pathomechanism are essential for the development of therapeutical clinical trials.