We searched the following databases using the following search queries: PubMed (search queries: “neurofilaments,” “sleep disorders and neurofilaments,” “OSA and neurofilaments,” “BDNF and OSA,” “neurodegeneration and OSA,” and “neurodegeneration and neurofilaments”); Google Scholar (search queries: “OSA and neurofilaments,” “sleep disorders and neurofilaments,” “insomnia and neurofilaments,” “neurofilaments and neurodegeneration,” “neurofilaments and OSA and cognition and biomarker,” “OSA and BDNF,” and “neurofilaments and sleep architecture”). This evidence concerns the gene BDNF and obstructive sleep apnea syndrome.