Mutation analysis ofCHCHD10in different neurodegenerative diseases

Sir, A recent study by Bannwarth et al. (2014) implicated CHCHD10 as a novel gene for amyotrophic lateral sclerosis/frontotemporal lobar degeneration (ALS/FTLD), reporting a p.S59L substitution (c.176C > T; NM_213720.2) in a large French kindred. Affected family members were presented with a complex phenotype that included symptoms of amyotrophic lateral sclerosis (ALS), frontotemporal lobar degeneration (FTLD), cerebellar ataxia, Parkinson’s disease and a mitochondrial myopathy associated with multiple mitochondrial DNA deletions. So far, seven missense CHCHD10 mutations have been reported in patients with a broad phenotypic range, including ALS/FTLD (p.S59L and p.P34S) (Bannwarth et al. , 2014; Chaussenot et al. , 2014), ALS (p.R15L and p.G66V) (Johnson et al. , 2014; Muller et al. , 2014), myopathy (p.R15S and p.G58R) (Ajroud-Driss et al. , 2015) and late-onset spinal motor neuronopathy (p.G66V) (Penttila et al. , 2015). All of them affect exon 2 (a mutational hotspot of CHCHD10 ). Notably, mitochondrial dysfunction has been implicated in several neurodegenerative diseases (Lin and Beal, 2006; Cozzolino et al. , 2013); however, there are no studies evaluating the contribution of CHCHD10 to pure FTLD, Parkinson’s disease or Alzheimer’s disease. Hence, we sequenced CHCHD10 exon 2 in 204 ALS, 153 Parkinson’s disease and 141 Alzheimer’s disease patients from Canada and 158 FTLD patients from Italy in addition to 497 control subjects from USA/UK, Canada and Italy. The cases of ALS and FTLD were free from mutations in SOD1 , GRN , FUS , TARDBP and MATR3 or a repeat expansion in C9orf72 . We identified a known CHCHD10 pathogenic p.R15L mutation (Johnson et al. , 2014; Muller et al. , 2014) in a patient with sporadic ALS (Patient 8807) (Fig. 1A), who developed symptoms involving his upper limb at 54 years of age and remains alive 12 years later. The p.R15L …