Mouse Cyp2a5 is an ortholog of human Cyp2a6, and the findings in this study may be extrapolated from mouse to human being. Cyp2a6 gene, which is highly polymorphic, has approximately 40 annotated allelic variants, and homozygosis for some of these alleles leads to a total lack of CYP2A6 activity. Individual difference in CYP2A6 expression and activity is due primarily to genetic polymorphisms in the Cyp2a6 gene (Raunio and Rahnasto-Rilla, 2012). There have been near 300 single nucleotide polymorphisms (SNPs) found in the Cyp2a6 upstream sequence, and polymorphism of CYP2A6 has been associated with smoking behavior, drug clearance and lung cancer risk (Di et al., 2009). Whether the polymorphisms of human Cyp2a6 affect sensitivity of patients to alcoholic fatty liver disease needs further studies.
