Gentile et al. [19] genotyped panel of SNPs involved in triptans pharmacokinetics and pharmacody-namics in a chronic migraine (CM) population. In particular they studied the 30 bp VNTR in MAO A (monoamine oxidase A) promoter, CYP 1A2 *1C and *1 F, CYP3A4 *1B and C825T SNP in the gene coding the G protein b3 subunit (GNB3). A significant association with CM was found for the long allele of monoamine oxidase A 30 bp VNTR and CYP1A2*1 F variant. The same authors performed an analysis of the association between genotypic and allelic frequencies of the analyzed SNPs and the grade of response to triptan administration: a significant correlation for MAOA uVNTR polymorphism was found. Further stratification of patients in abuser and non-abuser groups revealed a significant association with triptan overuse and, within the abusers, with drug response to the CYP1A2*1 F variant [20].