Table 2.

Polymorphisms linked to acute and chronic response to caffeine

SNP	Position	Acute effects	Long-term effects
CYP1A2
rs762551	Intron I pos. 734: C → A	Increased activity in smokers with A/A genotype (Sachse et al. 1999)	Caffeine consumption does not appear to differ between the genotypes (Cornelis et al. 2007) Risk of nonfatal myocardial infarction higher for subjects with C/C genotype (Cornelis et al. 2006) No association found for risk of Parkinson’s disease (Facheris et al. 2008)
rs35694136			No association found for risk of Parkinson’s disease (Facheris et al. 2008)
ADORA2A
rs5751876	1976 C/T	C/C genotype associated with greater caffeine sensitivity, sleep impairment, and increased beta activity during non-REM sleep (Retey et al. 2007) T/T genotype associated with greater anxiety after caffeine (Alsene et al. 2003; Childs et al. 2008)
rs35320474	2592 T/−	T/T genotype associated with greater anxiety after caffeine (Childs et al. 2008)	No association found for Parkinson’s disease or caffeine consumption (Tan et al. 2006)
rs3032740			No association found for risk of Parkinson’s disease (Facheris et al. 2008)
DRD2
rs1110976		Associated with greater levels of caffeine-induced anxiety (Childs et al. 2008)
COMT
rs4680	Nucleotide codon 158: Val/Met	Higher risk of acute myocardial infarction in alleles coding for low activity (Met/Met) (Happonen et al. 2006)