Mutations in C9ORF72 and the genes encoding TDP-43 and FUS cause familial forms of FTD/ALS which provides evidence to link the pathology and genetics of these diseases.
FTD usually belongs to the frontotemporal lobar degeneration (FTLD) disease group, and its familial forms are dominantly inherited and linked to a group of genes relevant to frontal and temporal brain pathology, such as MAPT, GRN, C9ORF72, TARDBP, CHMP2B, VCP, and FUS.
The identification of mutations in transactive response DNA-binding protein gene (TARDBP), fused in sarcoma (FUS) and, more recently, a GGGGCC-hexanucleotide repeat expansion in chromosome 9 open reading frame 72 (C9ORF72) and their link with familial ALS have provided new avenues of investigation and hypotheses on the pathophysiology of this devastating disease.
Patients were genotyped for C9orf72 (18.3%), SOD1 (12.2%), FUS (5%), TARDBP (3.7%), and UBQLN2 (2.4%) gene mutations, which together account for approximately 40% of familial ALS in Turkey.
Previously, we screened mutations in 5 ALS genes including SOD1 and FUS in 9 fALS and 249 sALS patients and found a total of 15 patients with either SOD1 (7 fALS and 3 sALS) or FUS (1fALS and 4 sALS) mutations.
In amyotrophic lateral sclerosis (ALS) patients with known genetic cause, mutations in chromosome 9 open reading frame 72 (C9orf72) and superoxide dismutase 1 (SOD1) account for most familial and late-onset sporadic cases, whereas mutations in fused in sarcoma (FUS) can be identified in just around 5% of familial and 1% of overall sporadic cases.
Mutations in the RNA- and DNA-binding proteins, fused in sarcoma (FUS) and transactive response DNA-binding protein 43 kDa (TDP-43), are responsible for 5-10% of familial and 1% of sporadic ALS cases.
Mutations in fused in sarcoma and/or translocated in liposarcoma (FUS, TLS or FUS) are linked to familial cases of amyotrophic lateral sclerosis (ALS).
Mutations in the gene encoding the RNA-binding protein fused in sarcoma (FUS) account for 4 - 5% of familial cases of amyotrophic lateral sclerosis (ALS).
We analysed the expression and localization of familial ALS-causing proteins, including transactive response DNA binding protein-43 (TDP-43), fused in sarcoma/translocated in liposarcoma (FUS/TLS), Cu/Zn superoxide dismutase (SOD1) and optineurin (OPTN) by immunohistochemistry.
The RNA-binding proteins, TDP-43 and FUS, are principal components of cytoplasmic inclusions found in motor neurons of ALS patients and mutations in TDP-43 and FUS are linked to familial and sporadic ALS.
Mutations in the gene encoding the RNA-binding protein fused in sarcoma (FUS) can cause familial and sporadic amyotrophic lateral sclerosis (ALS) and rarely frontotemproal dementia (FTD).
For example, FUS and TDP-43, which rank 1st and 10th among RRM-bearing prion candidates, form cytoplasmic inclusions in the degenerating motor neurons of ALS patients and mutations in TDP-43 and FUS cause familial ALS.
The RNA/DNA-binding proteins fused in sarcoma (FUS; also known as TLS) and TAR DNA binding protein-43 (TDP-43) have recently been shown to be genetically and pathologically associated with familial forms of ALS and FTD.