Distal hereditary motor neuropathies - 28/11/24
Highlights |
• | HSPB1, GARS, BICB2 and DNAJB2 among the most frequent dHMN genes. |
• | SIGMAR1 and VRK1 associated with a motor neuropathy and upper motoneuron involvement. With SORD mutations, therapeutic implications expected with aldose reductase inhibitors. With dHMN/BVVL due to riboflavin transporter deficiency, riboflavin treatment possible. |
Abstract |
Distal hereditary motor neuropathies (dHMN) are a group of heterogeneous hereditary disorders characterized by a slowly progressive distal pure motor neuropathy. Electrophysiology, with normal motor and sensory conduction velocities, can suggest the diagnosis of dHMN and guide the genetic study. More than thirty genes are currently associated with HMNs, but around 60 to 70% of cases of dHMN remain uncharacterized genetically. Recent cohort studies showed that HSPB1, GARS, BICB2 and DNAJB2 are among the most frequent dHMN genes and that the prevalence of the disease was calculated as 2.14 and 2.3 per 100,000. The determination of the different genes involved in dHMNs made it possible to observe a genotypic overlap with some other neurogenetic disorders and other hereditary neuropathies such as CMT2, mainly with the HSPB1, HSPB8, BICD2 and TRPV4 genes of AD-inherited transmission and recently observed with SORD gene of AR transmission which seems relatively frequent and potentially curable. Distal hereditary motor neuropathy that predominates in the upper limbs is linked mainly to three genes: GARS, BSCL2 and REEP1, whereas dHMN with vocal cord palsy is associated with SLC5A7, DCTN1 and TRPV4 genes. Among the rare AR forms of dHMN like IGHMBP2 and DNAJB2, the SIGMAR1 gene mutations as well as VRK1 variants are associated with a motor neuropathy phenotype often associated with upper motoneuron involvement. The differential diagnosis of these latter arises with juvenile forms of amyotrophic lateral sclerosis, that could be caused also by variations of these genes, as well as hereditary spastic paraplegia. A differential diagnosis of dHMN related to Brown Vialetto Van Laere syndrome due to riboflavin transporter deficiency is important to consider because of the therapeutic possibility.
Le texte complet de cet article est disponible en PDF.Keywords : Distal hereditary motor neuropathy (dHMN), Charcot-Marie-Tooth type 2 (CMT2), Juvenile amyotrophic lateral sclerosis, Hereditary spastic paraplegia, Brown Vialetto Van Laere syndrome
Plan
Vol 180 - N° 10
P. 1031-1036 - décembre 2024 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
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