Reply: Biallelic variants in the COQ7 gene cause distal hereditary motor neuropathy in two Chinese families.

Abstract

We read with interest the letter from Liu et al.1 reporting two patients affected by inherited neuropathies carrying novel biallelic COQ7 variants. These results independently confirm our initial observation that COQ7 mutations can cause distal hereditary motor neuropathy (dHMN) and expand the spectrum of COQ7 pathogenic variants.2 Our study identified a homozygous variant in the start codon of the main isoform (c.3G>T, MN_016138) of COQ7 gene in a family of three patients affected by dHMN.2 Here, the authors report from two independent families four new COQ7 variants in two patients: c.253-2A>T and c.467T>A (p.L156Q) in one patient, and c.160 C>T (p.R54W) and c.467T>G (p.L156R) in the other. Interestingly, the two patients presented with the same phenotype of distal motor neuropathy (dHMN) that we previously described. It confirms that dHMN belongs to the spectrum of COQ7-related neuropathies. The second patient reported here presented with pyramidal signs (Hoffman and Rossolimo signs), similar to two of the three patients reported in our study. Clinicians should therefore investigate COQ7 mutations in patients presenting with dHMN associated with pyramidal signs.