<h4>Aims</h4>To investigate the roles of neurotrophic factors on cognition in patients with Alzheimer's disease (AD) carrying Apolipoprotein E (APOE) ε4.<h4>Methods</h4>Totals of 173 patients with AD were divided into APOE ε4 carrier and non-carrier groups, and their demographics, cognition, and neurotrophic factors in cerebrospinal fluid (CSF) were compared. The gene discussed is APOE; the disease is early-onset autosomal dominant Alzheimer disease.