Centres of Excellence in Neurodegeneration.

Background Frontotemporal dementia is a heterogenous neurodegenerative disorder, with about a third of cases being genetic. Most of this genetic component is accounted for by mutations in GRN, MAPT, and C9orf72. In this study, we aimed to complement previous phenotypic studies by doing an international study of age at symptom onset, age at death, and disease duration in individuals with mutations in GRN, MAPT, and C9orf72. Methods In this international, retrospective cohort study, we collected data on age at symptom onset, age at death, and disease duration for patients with pathogenic mutations in the GRN and MAPT genes and pathological expansions in the C9orf72 gene through the Frontotemporal Dementia Prevention Initiative and from published papers. We used mixed effects models to explore differences in age at onset, age at death, and disease duration between genetic groups and individual mutations. We also assessed correlations between the age at onset and at death of each individual and the age at onset and at death of their parents and the mean age at onset and at death of their family members. Lastly, we used mixed effects models to investigate the extent to which variability in age at onset and at death could be accounted for by family membership and the specific mutation carried. Findings Data were available from 3403 individuals from 1492 families: 1433 with C9orf72 expansions (755 families), 1179 with GRN mutations (483 families, 130 different mutations), and 791 with MAPT mutations (254 families, 67 different mutations). Mean age at symptom onset and at death was 49•5 years (SD 10•0; onset) and 58•5 years (11•3; death) in the MAPT group, 58•2 years (9•8; onset) and 65•3 years (10•9; death) in the C9orf72 group, and 61•3 years (8•8; onset) and 68•8 years (9•7; death) in the GRN group. Mean disease duration was 6•4 years (SD 4•9) in the C9orf72 group, 7•1 years (3•9) in the GRN group, and 9•3 years (6•4) in the MAPT group. Individual age at onset and at death was significantly correlated with both parental age at onset and at death and with mean family age at onset and at death in all three groups, with a stronger correlation observed in the MAPT group (r=0•45 between individual and parental age at onset, r=0•63 between individual and mean family age at onset, r=0•58 between individual and parental age at death, and r=0•69 between individual and mean family age at death) than in either the C9orf72 group (r=0•32 individual and parental age at onset, r=0•36 individual and mean family age at onset, r=0•38 individual and parental age at death, and r=0•40 individual and mean family age at death) or the GRN group (r=0•22 individual and parental age at onset, r=0•18 individual and mean family age at onset, r=0•22 individual and parental age at death, and r=0•32 individual and mean family age at death). Modelling showed that the variability in age at onset and at death in the MAPT group was explained partly by the specific mutation (48%, 95% CI 35-62, for age at onset; 61%, 47-73, for age at death), and even mor...

Background: Frontotemporal dementia (FTD) is frequently caused by genetic mutations in GRN, C9orf72 and MAPT. Neurofilament light chain (NfL) is a promising blood biomarker in genetic FTD, with elevated levels in symptomatic mutation carriers. A better understanding of NfL dynamics is essential for its use in upcoming therapeutic trials. We investigated longitudinal serum NfL trajectories in presymptomatic and symptomatic genetic FTD. over time was associated with atrophy rate in several grey matter regions, but not with rate of change in clinical parameters. Interpretation: This study confirms the value of blood NfL as a disease progression biomarker in genetic FTD and indicates that longitudinal NfL measurements could help identify mutation carriers approaching symptom onset and capture the rate of brain atrophy. The stable levels in C9orf72-and MAPT-associated FTD offer potential for NfL as a marker of treatment effect in therapeutic trials.

Background and Objectives:To investigate the natural history and outcomes following treatment for spontaneous amyloid-related imaging abnormalities (ARIA)-like in cerebral amyloid angiopathy-related inflammation (CAA-ri).Methods:A multicenter, hospital-based, longitudinal, prospective observational study of inpatients meeting CAA-ri diagnostic criteria, recruited through the iCAβ International Network, in the period January 2013 - March 2017. A protocol for systematic data collection at first-ever presentation and at subsequent in-person visits, including T1-weighted, GRE-T2*, fluid-suppressed T2-weighted (FLAIR), and T1 post-gadolinium contrast-enhancement images aquired on 1.5T MRI, was employed at 3, 6, 12, 24-months follow-up. Centralized reads of MRI images were performed blinded to clinical, therapeutic, and time-points information. Main outcomes were survival, clinical and radiological recovery, intracerebral hemorrhage (ICH), and recurrence of CAA-ri.Results:The study enrolled 113 participants (10.6% definite, 71.7% probable, and 17.7% possible CAA-ri), mean age 72.9 years, 43.4% female, 37.1% APOEε4 carriers. 36.3% had a history of Alzheimer’s disease, 33.6% of ICH. A history of ICH, as well as the occurrence of new ICH at follow-up, was more common in patients with cortical superficial siderosis at baseline (52.6% vs 14.3%; p< 0.0001 and 19.3% vs 3.6%; p<0.009, respectively). After the first-ever presentation of CAA-ri, 70.3% (95% CI, 61.6-78.5) and 84.1% (95% CI, 76.2-90.6) clinically recovered within three and twelve months, followed by radiological recovery in 45.1% (95% CI, 36.4 - 54.8) and 77.4% (95% CI, 67.7 - 85.9), respectively. After clinicoradiological resolution of the first-ever episode, 38,3% (95% CI, 22.9 - 59.2) had at least one recurrence within the following 24 months. Recurrence was more likely if intravenous high dose corticosteroid pulse therapy was suddenly stopped compared to slow oral tapering-off (Hazard Ratio 4.68; 95% CI, 1.57-13.93; p=0.006).Discussion:These results from the largest longitudinal cohort registry of patients with CAA-ri support the transient and potentially relapsing inflammatory nature of the clinical-radiological acute manifestations of the disease and the effectiveness of slow oral tapering-off after intravenous corticosteroid pulse therapy in preventing recurrences. Our results highlight the importance of differential diagnosis for spontaneous ARIA-like events in Aβ-driven diseases, including treatment-related ARIA in Alzheimer’s disease patients exposed to immunotherapy drugs.