Investigating the role of ALS genes CHCHD10 and TUBA4A in Belgian FTD-ALS spectrum patients

Mutation screening and phenotypic profiling of 2 amyotrophic lateral sclerosise-(ALS) and fronto-temporal dementiae-(FTD) associated genes, CHCHD10 and TUBA4A, were performed in a Belgian cohort of 459 FTD, 28 FTD-ALS, and 429 ALS patients. In CHCHD10, we identified a novel nonsense mutation (p. Gln108*) in a patient with atypical clinical FTD and pathology-confirmed Parkinson's disease (1/459, 0.22%) leading to loss of transcript. We further observed 3 previously described missense variants (p. Pro34Ser, p. Pro80Leu, and p. Pro96Thr) that were also present in the matched control series. In TUBA4A, we detected a novel frameshift mutation (p. Arg64Glyfs* 90) leading to a truncated protein in 1 FTD patient (1/459 of 0.22%) with family history of Parkinson's disease and cognitive impairment, and a novel missense mutation (p. Thr381Met) in 2 sibs with familial ALS and memory problems (1 index patient/ 429, 0.23%) in whom we previously identified a pathogenic Chromosome 9 open reading frame 72 repeat expansion mutation. The present study confirms the role of CHCHD10 and TUBA4A in the FTD-ALS spectrum, although genetic variations in these 2 genes are extremely rare in the Belgian population and often associated with symptomatology of related neurodegenerative diseases including Parkinson's disease and Alzheimer's disease.Mutation screening and phenotypic profiling of 2 amyotrophic lateral sclerosise-(ALS) and fronto-temporal dementiae-(FTD) associated genes, CHCHD10 and TUBA4A, were performed in a Belgian cohort of 459 FTD, 28 FTD-ALS, and 429 ALS patients. In CHCHD10, we identified a novel nonsense mutation (p. Gln108*) in a patient with atypical clinical FTD and pathology-confirmed Parkinson's disease (1/459, 0.22%) leading to loss of transcript. We further observed 3 previously described missense variants (p. Pro34Ser, p. Pro80Leu, and p. Pro96Thr) that were also present in the matched control series. In TUBA4A, we detected a novel frameshift mutation (p. Arg64Glyfs* 90) leading to a truncated protein in 1 FTD patient (1/459 of 0.22%) with family history of Parkinson's disease and cognitive impairment, and a novel missense mutation (p. Thr381Met) in 2 sibs with familial ALS and memory problems (1 index patient/ 429, 0.23%) in whom we previously identified a pathogenic Chromosome 9 open reading frame 72 repeat expansion mutation. The present study confirms the role of CHCHD10 and TUBA4A in the FTD-ALS spectrum, although genetic variations in these 2 genes are extremely rare in the Belgian population and often associated with symptomatology of related neurodegenerative diseases including Parkinson's disease and Alzheimer's disease.A