DDX41 and early-onset autosomal dominant Alzheimer disease: CSF analysis was performed as well (pressure, protein, cell count, IgG index, oligoclonal bands, cytology, 14-3-3 protein, RT-QuIC test, PCR for JCV DNA, tau and beta-amyloid as biomarkers for Alzheimer disease, anti-GAD and anti-NMDAR Abs titer) as well as urine analysis (urinary 24-h copper excretion to exclude Wilson disease).