To this end, we differentiated 9 induced pluripotent stem cell lines derived from a control subject, a sporadic FTD case and an FTD patient with progranulinS116X mutation.
No study but one has suggested the presence of white matter hyperintensities (WMHs) in frontotemporal dementia (FTD), limited to 4 cases carrying pathogenic Granulin (GRN) gene mutations.
Longitudinal analyses revealed a significantly stronger decrease in CBF in frontal, temporal, parietal, and subcortical areas in the total group of mutation carriers and the GRN subgroup, with the strongest decrease in two mutation carriers who converted to clinical FTD during follow-up.
Progranulin (GRN) loss-of-function mutations leading to progranulin protein (PGRN) haploinsufficiency are prevalent genetic causes of frontotemporal dementia.
Among them, variants in the microtubule-associated protein tau (MAPT), GRN, and chromosome 9 open-reading frame 72 (C9orf72) genes are considered the major cause of FTD.
Further, we compared genotype-phenotype data of TBK1 carriers with frontotemporal dementia (n = 7), with those of frontotemporal dementia patients with a C9orf72 repeat expansion (n = 65) or a GRN mutation (n = 52) and with frontotemporal dementia patients (n = 259) negative for mutations in currently known causal genes.
Altered progranulin levels play a major role in neurodegenerative diseases, like Alzheimer's dementia (AD), frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS), even in the absence of GRN mutations.
Healthy, at-risk, first-degree relatives of patients with FTD who had a MAPT (n = 13) or GRN mutation (n = 30) and healthy controls (n = 39) underwent neuropsychological assessment at baseline and 2-year follow-up.
Here, we investigated the frequency of PGRN mutations in FTD patients (n = 116) from a clinical cohort of south India and detected one novel mutation located on exon 12 in a familial behavioral variant FTD patient (accounting for ∼1% of total FTD cases and 6% of familial FTD cases).
Surprisingly, we found that most of the FTLD-TDP-GRN brains are characterized by a huge reduction of Tau protein expression without any decrease in Tau mRNA levels.
In this longitudinal study, 58 subjects were identified who had at least two MRI and MAPT mutations (n = 21), GRN mutations (n = 11), C9ORF72 repeat expansions (n = 11) or sporadic FTD (n = 15).
UBQLN2 was found to be a potent regulator of the levels of the FTD-linked secretory factor progranulin, possibly via the endosomal system, and ALS-linked mutations disturbed these functional consequences.
Increasing progranulin levels and blockade of the ERK1/2 pathway: upstream and downstream strategies for the treatment of progranulin deficient frontotemporal dementia.
Mutations in three genes [chromosome 9 open-reading-frame 72 (C9ORF72); microtubule-associated protein tau (MAPT) and progranulin (GRN)] account for the vast majority of familial, and a proportion of sporadic, frontotemporal dementia (FTD) cases.
We screened 37 AD, 8 mild cognitive impairment (MCI), 3 AD and CVD (cerebrovascular disease), 3 MCI and CVD, 8 frontotemporal dementia (FTD) and 2 progressive supranuclear palsy (PSP) patients, and 28 normal controls (NCs).We sequenced PSEN1, PSEN2 and APP (EOAD risk factors), as well as MAPT, GRN and TARDBP for all cases and NCs, and analysed the APOE, CLU, CR1 and PICALM genotypes as well as the MAPT and ACE haplotypes (LOAD risk factors) for the AD (n = 37) and AD + MCI (n = 45) cases and NCs (n = 28).We identified variants in PSEN1, PSEN2 and TARDBP across a range of phenotypes (AD, AD and CVD, FTD and PSP), suggesting that screening of all known candidate genes of Alzheimer's and non-Alzheimer's forms of dementias in all dementia cases might be warranted.
These preliminary results suggest that the proteasomal degradation pathway plays a role in the pathogenesis of FTD associated with TDP-43 pathology, although different proteins are altered in carriers of GRN mutations as compared with carriers of the C9ORF72 expansion.
Co-occurrence of the C9ORF72 expansion and a novel GRN mutation in a family with alternative expression of frontotemporal dementia and amyotrophic lateral sclerosis.
Parkinsonism can be the presenting feature of frontotemporal dementia due to Progranulin (GRN) mutations or develop over the course of the disease, mimicking idiopathic Parkinson's disease or atypical parkinsonism.