Search Results (30)

Pathogenic GRN variants that reduce progranulin (PGRN) levels cause frontotemporal dementia (FTD). To facilitate model development, we generated induced pluripotent stem cells (iPSCs) from dermal fibroblasts of two family members carrying the GRN c.1009C>T (p.Q337X) pathogenic variant—one symptomatic and one asymptomatic—as well as a non-carrier first-degree relative serving as a genetically matched control. The obtained iPSC lines were validated for pluripotency markers (Nanog, Sox2, Oct4, and TRA1-1-81), genomic integrity, and differentiation potential. The obtained iPSC lines were subsequently directed toward neuroepithelial stem (NES) cells. NES identity was confirmed by the expression of lineage-specific markers, including Nestin and Sox2 (assessed by immunocytochemistry), as well as SOX1, PLAGL1, and MKI67 (evaluated by real-time PCR). Furthermore, GRN mRNA levels were significantly reduced in iPSC and NES lines derived from mutation carriers compared to control cells. The established iPSC and NES cell lines represent a platform for modeling progranulin-deficient FTD. The symptomatic and asymptomatic carrier-derived lines obtained from the same family offer a unique opportunity to study disease progression across clinical phases. The control line, derived from a related (first-degree) non-carrier, minimizes genetic background variability. Their utility of the established cell lines extends to therapeutic drug screening and further differentiation into neuronal, non-neuronal, and organoid models. Full article

Frontotemporal dementia (FTD) represents a cluster of adult-onset neurodegenerative diseases resulting from a combination of genetic and epigenetic factors. Currently, treatment is symptomatic and there are no licensed disease-modifying therapies available. The aim of this review was to provide an overview of ongoing or recently completed clinical studies targeting disease modification in FTD. A structured search of interventional trials of pharmacological compounds was conducted on three clinical trial registries (National Library of Medicine Clinical Trials, European Union Clinical Trials, and the Australian New Zealand Clinical Trials registries) up to September 2025. Twelve interventional trials were found. Half targeted autosomal-dominant progranulin (GRN) mutations (n = 6) and half examined therapies targeting neuroinflammatory-induced sporadic FTD (n = 6). The interim results of the early-phase (1/2) randomized controlled trials (RCTs), comprising three ongoing gene replacement studies (PROCLAIM, ASPIRE-FTD, upliFT-D) and one immune-modulating monoclonal antibody (INFRONT, now in phase 3)—all targeting the FTD-GRN mutation—show safety, tolerability, and effectiveness in restoring progranulin levels. Two recently completed phase 2 RCTs for sporadic FTD targeting neuroinflammation, the PEA-FTD and C9orf72 ALS/FTD trials, show disease-modifying potential. While interim results from six trials suggest clear mechanistic efficacy, prospective high-quality later-phase RCTs are required to ascertain long-term clinical efficacy. Since familial FTD encompasses less than half of the people with this disease, it is important to continue exploring the underlying pathophysiology, neuroimmunology, and treatment of epigenetic-induced sporadic FTD. Full article

Frontotemporal dementia (FTD) is the second most common early-onset dementia after Alzheimer’s disease, characterized by progressive neurodegeneration primarily in the frontal and temporal lobes. Granulin (GRN) gene for encoding the progranulin (PGRN) protein was a key genetic contributor to FTD. PGRN was a multifunctional protein involved in lysosomal function, neuroinflammation, and neuronal survival. This review discusses the contributions of GRN haploinsufficiency to FTD pathogenesis with an emphasis on genetic mutations, downstream cellular consequences, relevant animal and cellular models, and emerging therapeutic strategies. Loss-of-function mutations in GRN were responsible up to ~50% reduction in PGRN levels, resulting in lysosomal dysfunction, TDP-43 aggregation, impaired microglial homeostasis, and enhanced neuroinflammation. Multiple in vitro and in vivo models recapitulated these pathological features. Novel therapeutic approaches, such as AAV-mediated gene therapy, stop codon readthrough compounds, SORT1 inhibitors, and antisense oligonucleotides, were investigated to restore PGRN levels and to mitigate disease progressions. However, challenges included the oncogenic risks of overexpression and the limited translational success in clinical trials to date. Targeting GRN haploinsufficiency became a promising avenue for FTD therapy. Improved models and refined delivery systems would be essential to develop safe and effective treatments. Future work should also focus on biomarker-guided interventions in presymptomatic mutation carriers. Full article

Background and objectives: Frontotemporal dementia (FTD) is a heterogeneous neurodegenerative disorder with autosomal dominant forms most often linked to MAPT, GRN, and C9orf72. We aimed to evaluate the prevalence of pathogenic variants in these genes in a hospital-based cohort of FTD patients assessed at a tertiary referral center in southeastern Serbia. Methods: We studied 58 consecutive patients with FTD spectrum syndromes evaluated at a tertiary referral center. All underwent standardized neurological, neuropsychological, and imaging assessments, and family history was recorded. Genetic testing included validated assays for C9orf72 repeat expansions and next-generation sequencing of MAPT and GRN. Results: Women comprised 53.45% of the cohort. The mean age was 67.88 years, with mean onset at 61.70 years. Behavioral variant FTD predominated (75.87%), while language forms were less frequent. Positive family history was present in 16 patients (27.59%). Pathogenic variants were identified in three individuals (5.17%): two unrelated carriers of the intronic MAPT mutation c.1920+16C>T and one patient with a C9orf72 expansion. No GRN variants were detected. Mutation frequency was 18.75% in familial cases, while none were found among sporadic patients (p = 0.018). Four of nine relatives were asymptomatic MAPT mutation carriers. Conclusions: This first genetic study of FTD in southeastern Serbia revealed a lower mutation frequency than in Northern and Western Europe, but similar to cohorts from Southeastern Europe. The detection of MAPT c.1920+16C>T in two unrelated families extends the geographic range of this splice-site variant and underscores the importance of systematic genetic testing and larger collaborative studies in the Balkans. Full article

The presence of cognitive lapses in the post-COVID-19 period, particularly among younger individuals, suggests a potential genetic predisposition. This case–control study aimed to assess the association between neurodegeneration-associated genes and cognitive declines in the post-COVID-19 Armenian population under the age of 65. In addition, we examined other contributing factors, including depressive symptoms, hypovitaminosis D, vitamin B12 and B9 deficiencies, and some viral infections, as potential confounders or effect modifiers. A total of 162 participants (ages 19–65, Med = 43), who were exposed to SARS-CoV-2 in Armenia between 2020 and 2022, participated in this study. Standardized assessments, including the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and the Montreal Cognitive Assessment (MoCA), were used to evaluate cognitive functions and mental status, while the Patient Health Questionnaire-9 (PHQ-9) was utilized to assess depressive symptoms. Clinical interview data, comprising yes/no self-reports regarding the presence of cognitive problems and depressive symptoms, were also included. Genetic analysis identified copy number variations (CNVs) in the APP, PSEN1, PSEN2, MAPT, and GRN genes, while viral infections (HSV-1, HSV-2, CMV, EBV, HIV, SARS-CoV-2, Hepatitis A, B, and C) and vitamin D, B12, and B9 deficiencies were measured. Lower cognitive performance was associated with CNVs in PSEN1 (exons 1, 9, 12), GRN (exons 1, 6, 12), and MAPT (exons 2, 8), along with viral infections (HSV-1, HSV-2, HAV-2). The findings indicate that post-COVID-19 cognitive problems are multifactorial and are linked to genetic mutations, viral infections, age, gender, and folic acid deficiency. Full article

This narrative review explores the current landscape of blood biomarkers in Frontotemporal dementia (FTD). Neurofilament light chain (NfL) may be useful in the differentiation of behavioral variant FTD from primary psychiatric disorders (PPDs) or dementia with Lewy bodies (DLB). In prodromal FTD and presymptomatic mutation carriers (GRN, MAPT, C9orf72), elevated NfL may herald pheno-conversion to full-blown dementia. Baseline NfL correlates with steeper neuroanatomical changes and cognitive, behavioral and functional decline, making NfL promising in monitoring disease progression. Phosphorylated neurofilament heavy chain (pNfH) levels have a potential limited role in the demarcation of the conversion stage to full-blown FTD. Combined NfL and pNfH measurements may allow a wider stage stratification. Total tau levels lack applicability in the framework of FTD. p-tau, on the other hand, is of potential value in the discrimination of FTD from Alzheimer’s dementia. Progranulin concentrations could serve the identification of GRN mutation carriers. Glial fibrillary acidic protein (GFAP) may assist in the differentiation of PPDs from behavioral variant FTD and the detection of GRN mutation carriers (additional research is warranted). Finally, TAR DNA-binding protein-43 (TDP-43) appears to be a promising diagnostic biomarker for FTD. Its potential in distinguishing TDP-43 pathology from other FTD-related pathologies requires further research. Full article

Alzheimer’s disease (AD) and Frontotemporal lobar degeneration (FTLD) represent the most common forms of neurodegenerative dementias with a highly phenotypic variability. Herein, we investigated the role of genetic variants related to the immune system and inflammation as genetic modulators in AD and related dementias. In patients with sporadic AD/FTLD (n = 300) and GRN/C9orf72 mutation carriers (n = 80), we performed a targeted sequencing of 50 genes belonging to the immune system and inflammation, selected based on their high expression in brain regions and low tolerance to genetic variation. The linear regression analyses revealed two genetic variants: (i) the rs1049296 in the transferrin (TF) gene, shown to be significantly associated with age at onset in the sporadic AD group, anticipating the disease onset of 4 years for each SNP allele with respect to the wild-type allele, and (ii) the rs7550295 in the calsyntenin-1 (CLSTN1) gene, which was significantly associated with age at onset in the C9orf72 group, delaying the disease onset of 17 years in patients carrying the SNP allele. In conclusion, our data support the role of genetic variants in iron metabolism (TF) and in the modulation of the calcium signalling/axonal anterograde transport of vesicles (CLSTN1) as genetic modulators in AD and FTLD due to C9orf72 expansions. Full article

Alzheimer’s Disease (AD) and Frontotemporal Dementia (FTD) are the two major neurodegenerative diseases with distinct clinical and neuropathological profiles. The aim of this report is to conduct a population-based investigation in well-characterized APP, PSEN1, PSEN2, MAPT, GRN, and C9orf72 mutation carriers/pedigrees from the north, the center, and the south of Italy. We retrospectively analyzed the data of 467 Italian individuals. We identified 21 different GRN mutations, 20 PSEN1, 11 MAPT, 9 PSEN2, and 4 APP. Moreover, we observed geographical variability in mutation frequencies by looking at each cohort of participants, and we observed a significant difference in age at onset among the genetic groups. Our study provides evidence that age at onset is influenced by the genetic group. Further work in identifying both genetic and environmental factors that modify the phenotypes in all groups is needed. Our study reveals Italian regional differences among the most relevant AD/FTD causative genes and emphasizes how the collaborative studies in rare diseases can provide new insights to expand knowledge on genetic/epigenetic modulators of age at onset. Full article

In Portugal, heterozygous loss-of-function mutations in the progranulin (GRN) gene account for approximately half of the genetic mediated forms of frontotemporal dementia (FTD). GRN mutations reported thus far cause FTD through a haploinsufficiency disease mechanism. Herein, we aim to unveil the GRN mutation spectrum, investigated in 257 FTD patients and 19 family members from the central/north region of Portugal using sequencing methods. Seven different pathogenic variants were identified in 46 subjects including 40 patients (16%) and 6 relatives (32%). bvFTD was the most common clinical presentation among the GRN mutation patients, who showed a global pattern of moderate-to-severe frontotemporoparietal deficits in the neuropsychological evaluation. Interestingly, two mutations were novel (p.Thr238Profs*18, p.Leu354Profs*16), and five were previously described, although three of them only in the Portuguese population, suggesting a population-specific GRN mutational spectrum. The subjects harboring a GRN mutation showed a significant reduction in serum PGRN levels, supporting the pathogenic nature of these variants. This work broadens the mutation spectrum of GRN and the identification of the underlying GRN mutations provided an accurate genetic counselling and allowed the enrolment of subjects with GRN mutations (both asymptomatic and symptomatic) in ongoing clinical trials, which is essential to test new drugs for the disease. Full article

Immuno-neurology is an emerging therapeutic strategy for dementia and neurodegeneration designed to address immune surveillance failure in the brain. Microglia, as central nervous system (CNS)-resident myeloid cells, routinely perform surveillance of the brain and support neuronal function. Loss-of-function (LOF) mutations causing decreased levels of progranulin (PGRN), an immune regulatory protein, lead to dysfunctional microglia and are associated with multiple neurodegenerative diseases, including frontotemporal dementia caused by the progranulin gene (GRN) mutation (FTD-GRN), Alzheimer’s disease (AD), Parkinson’s disease (PD), limbic-predominant age-related transactivation response deoxyribonucleic acid binding protein 43 (TDP-43) encephalopathy (LATE), and amyotrophic lateral sclerosis (ALS). Immuno-neurology targets immune checkpoint-like proteins, offering the potential to convert aging and dysfunctional microglia into disease-fighting cells that counteract multiple disease pathologies, clear misfolded proteins and debris, promote myelin and synapse repair, optimize neuronal function, support astrocytes and oligodendrocytes, and maintain brain vasculature. Several clinical trials are underway to elevate PGRN levels as one strategy to modulate the function of microglia and counteract neurodegenerative changes associated with various disease states. If successful, these and other immuno-neurology drugs have the potential to revolutionize the treatment of neurodegenerative disorders by harnessing the brain’s immune system and shifting it from an inflammatory/pathological state to an enhanced physiological/homeostatic state. Full article

In this manuscript, we introduced a French EOAD patient in Korea who carried the presenilin-1 (PSEN1) Glu318Gly mutations with four possible risk variants, including sortilin-related receptor 1 (SORL1) Glu270Lys, ATP-binding cassette subfamily A member 7 (ABCA7) Val1946Met, translocase of outer mitochondrial membrane 40 (TOMM40) Arg239Trp, and granulin (GRN) Ala505Gly. The patient started to present memory decline and behavioral dysfunction in his early 60s. His brain imaging presented amyloid deposits by positron emission tomography (PET-CT). The multimer detection system (MDS) screening test for plasma for amyloid oligomers was also positive, which supported the AD diagnosis. It was verified that PSEN1 Glu318Gly itself may not impact amyloid production. However, additional variants were found in other AD and non-AD risk genes, as follows: SORL1 Glu270Lys was suggested as a risk mutation for AD and could increase amyloid peptide production and impair endosome functions. ABCA7 Val1946Met was a novel variant that was predicted to be damaging. The GRN Ala505Gly was a variant with uncertain significance; however, it may reduce the granulin levels in the plasma of dementia patients. Pathway analysis revealed that PSEN1 Glu318Gly may work as a risk factor along with the SORL1 and ABCA7 variants since pathway analysis revealed that PSEN1 could directly interact with them through amyloid-related and lipid metabolism pathways. TOMM40 and PSEN1 could have common mechanisms through mitochondrial dysfunction. It may be possible that PSEN1 Glu318Gly and GRN Ala505Gly would impact disease by impairing immune-related pathways, including microglia and astrocyte development, or NFkB-related pathways. Taken together, the five risk factors may contribute to disease-related pathways, including amyloid and lipid metabolism, or impair immune mechanisms. Full article

Frontotemporal lobar degeneration (FTLD) belongs to a heterogeneous group of highly complex neurodegenerative diseases and represents the second cause of presenile dementia in individuals under 65. Frontotemporal-TDP is a subgroup of frontotemporal dementia characterized by the aggregation of abnormal protein deposits, predominantly transactive response DNA-binding protein 43 (TDP-43), in the frontal and temporal brain regions. These deposits lead to progressive degeneration of neurons resulting in cognitive and behavioral impairments. Limbic age-related encephalopathy (LATE) pertains to age-related cognitive decline primarily affecting the limbic system, which is crucial for memory, emotions, and learning. However, distinct, emerging research suggests a potential overlap in pathogenic processes, with some cases of limbic encephalopathy displaying TDP-43 pathology. Genetic factors play a pivotal role in both disorders. Mutations in various genes, such as progranulin (GRN) and chromosome 9 open reading frame 72 (C9orf72), have been identified as causative in frontotemporal-TDP. Similarly, specific genetic variants have been associated with an increased risk of developing LATE. Understanding these genetic links provides crucial insights into disease mechanisms and the potential for targeted therapies. Full article

Frontotemporal lobar degeneration (FTLD) includes a heterogeneous group of disorders pathologically characterized by the degeneration of the frontal and temporal lobes. In addition to major genetic contributors of FTLD such as mutations in MAPT, GRN, and C9orf72, recent work has identified several epigenetic modifications including significant differential DNA methylation in DLX1, and OTUD4 loci. As aging remains one of the major risk factors for FTLD, we investigated the presence of accelerated epigenetic aging in FTLD compared to controls. We calculated epigenetic age in both peripheral blood and brain tissues of multiple FTLD subtypes using several DNA methylation clocks, i.e., DNAmClock_Multi, DNAmClock_Hannum, DNAmClock_Cortical, GrimAge, and PhenoAge, and determined age acceleration and its association with different cellular proportions and clinical traits. Significant epigenetic age acceleration was observed in the peripheral blood of both frontotemporal dementia (FTD) and progressive supranuclear palsy (PSP) patients compared to controls with DNAmClock_Hannum, even after accounting for confounding factors. A similar trend was observed with both DNAmClock_Multi and DNAmClock_Cortical in post-mortem frontal cortex tissue of PSP patients and in FTLD cases harboring GRN mutations. Our findings support that increased epigenetic age acceleration in the peripheral blood could be an indicator for PSP and to a smaller extent, FTD. Full article

Loss-of-function (LOF) mutations in GRN gene, which encodes progranulin (PGRN), cause frontotemporal lobar degeneration with TDP-43 inclusions (FTLD-TDP). FTLD-TDP is one of the most common forms of early onset dementia, but its pathogenesis is not fully understood. Mitochondrial dysfunction has been associated with several neurodegenerative diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD) and amyotrophic lateral sclerosis (ALS). Here, we have investigated whether mitochondrial alterations could also contribute to the pathogenesis of PGRN deficiency-associated FTLD-TDP. Our results showed that PGRN deficiency induced mitochondrial depolarization, increased ROS production and lowered ATP levels in GRN KD SH-SY5Y neuroblastoma cells. Interestingly, lymphoblasts from FTLD-TDP patients carrying a LOF mutation in the GRN gene (c.709-1G > A) also demonstrated mitochondrial depolarization and lower ATP levels. Such mitochondrial damage increased mitochondrial fission to remove dysfunctional mitochondria by mitophagy. Interestingly, PGRN-deficient cells showed elevated mitochondrial mass together with autophagy dysfunction, implying that PGRN deficiency induced the accumulation of damaged mitochondria by blocking its degradation in the lysosomes. Importantly, the treatment with two brain-penetrant CK-1δ inhibitors (IGS-2.7 and IGS-3.27), known for preventing the phosphorylation and cytosolic accumulation of TDP-43, rescued mitochondrial function in PGRN-deficient cells. Taken together, these results suggest that mitochondrial function is impaired in FTLD-TDP associated with LOF GRN mutations and that the TDP-43 pathology linked to PGRN deficiency might be a key mechanism contributing to such mitochondrial dysfunction. Furthermore, our results point to the use of drugs targeting TDP-43 pathology as a promising therapeutic strategy for restoring mitochondrial function in FTLD-TDP and other TDP-43-related diseases. Full article

Frontotemporal Dementia (FTD) represents a highly heritable neurodegenerative disorder. Most of the heritability is caused by autosomal dominant mutations in the Microtubule-Associated Protein Tau (MAPT), Progranulin (GRN), and the pathologic exanucleotide expansion of C9ORF72 genes. At the pathological level, either the tau or the TAR DNA-binding protein (TDP-43) account for almost all cases of FTD. Pathogenic mechanisms are just arising, and the emerging role of non-coding RNAs (ncRNAs), such as microRNAs (miRNA) and long non-coding RNAs (lncRNAs), have become increasingly evident. Using specific arrays, an exploratory analysis testing the expression levels of 84 miRNAs and 84 lncRNAs has been performed in a population consisting of 24 genetic FTD patients (eight GRN, eight C9ORF72, and eight MAPT mutation carriers), eight sporadic FTD patients, and eight healthy controls. The results showed a generalized ncRNA downregulation in patients carrying GRN and C9ORF72 when compared with the controls, with statistically significant results for the following miRNAs: miR-155-5p (Fold Change FC: 0.45, p = 0.037 FDR = 0.52), miR-15a-5p (FC: 0.13, p = 0.027, FDR = 1), miR-222-3p (FC: 0.13, p = 0.027, FDR = 0.778), miR-140-3p (FC: 0.096, p = 0.034, FRD = 0.593), miR-106b-5p (FC: 0.13, p = 0.02, FDR = 0.584) and an upregulation solely for miR-124-3p (FC: 2.1, p = 0.01, FDR = 0.893). Conversely, MAPT mutation carriers showed a generalized robust upregulation in several ncRNAs, specifically for miR-222-3p (FC: 22.3, p = 7 × 10⁻⁶, FDR = 0.117), miR-15a-5p (FC: 30.2, p = 0.008, FDR = 0.145), miR-27a-3p (FC: 27.8, p = 6 × 10⁻⁶, FDR = 0.0005), miR-223-3p (FC: 18.9, p = 0.005, FDR = 0.117), and miR-16-5p (FC: 10.9, p = 5.26 × 10⁻⁵, FDR = 0.001). These results suggest a clear, distinctive pattern of dysregulation among ncRNAs and specific enrichment gene pathways between mutations associated with the TDP-43 and tau pathologies. Nevertheless, these preliminary results need to be confirmed in a larger independent cohort. Full article