Concerning the four SNPs of interest and the disease-related factors, cognitive impairment (SNPs of APOE, ADH1B, MTHFR), alcohol abuse (ADH1B variant), caffeine consumption (SNPs of CYP2A1, MTHFR), and homocysteine levels (MTHFR variant) appeared as the mostly represented traits. The gene discussed is MTHFR; the disease is alcohol abuse.