"The DESCRIBE-ALS-FTD study: a prospective multicenter observational study of the ALS-FTD spectrum".

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) exhibit significant clinical, genetic and neuropathological abnormalities, and are regarded as belonging to a common disease spectrum, referred to as the ALS-FTD spectrum disorders. Our understanding of the underlying mechanisms of these diseases has advanced significantly, including molecular neuropathology, genetics and molecular pathophysiology. The heterogeneity of these diseases poses significant challenges to translational research and drug development, particularly in sporadic cases. Consequently, there is an urgent need to improve patient stratification for the successful execution of future clinical trials. We here describe the study design of the DESCRIBE-ALS/FTD study which aims to address this research gap by undertaking a systematic sampling of patients from the ALS FTD spectrum, encompassing all possible disease variants. The main objective of the study is to systematically document detailed cross-sectional phenotyping and the temporal progression of motor and neuropsychological abnormalities that occur in both ALS and FTD. Additionally, it seeks to systematically correlate these abnormalities with genetics and potentially predictive biomarkers including longitudinal biomaterial sampling, brain imaging and brain banking. Furthermore, first-degree relatives of patients with disease-causing gene variants undergo the same assessments to also sample presymptomatic risk gene carriers. With this prospective registry study we aim to generate datasets which will help researchers identifying different disease traits in people with sporadic and genetic ALS and FTD and to develop biomarkers to identify preclinical and prodromal disease stages.