Franciosi JP, et al. - The assumption explored herein was that that the distribution of the extensive metabolizer (EM) phenotypes among children undergoing anti-reflux surgery (ARS) after failing proton pump inhibitor (PPI) therapy would vary compared to controls (children with no history of ARS). As per the findings, the carriage of CYP2C19*17 allele corresponding to the EM phenotype demonstrated a link with ARS, among children with medically refractory gastroesophageal reflux disease (GERD) despite PPI therapy. In order to contemplate if CYP2C19 genotype-guided dosing improved the response to PPI therapy without a corresponding increase in adverse effects in children, additional analyses were necessitated.