Core biomarkers of AD have been studied in adults with DS, namely cerebrospinal fluid (CSF) Aβ1–42 and amyloid PET, CSF phosphorylated tau and tau PET, neuronal injury biomarkers such as CSF total tau and neurofilament light chain (NfL), or regional brain atrophy on MRI [8,12]. The gene discussed is NEFL; the disease is Alzheimer disease.