In the present study, for the first time we used a comprehensive approach that could enable early diagnosis of canine patients with mild cognitive disorders (MiCI) involving CADES questionnaires, peripheral biomarkers (AST, ALT, Na, and Cl), and biomarkers for neurodegeneration (NFL, TAU protein, and Aβ42 peptide) in blood serum. This evidence concerns the gene NEFL and cognitive disorder.