A total of 261 patients with AP (174 with a sentinel attack, and 87 with recurrent attacks) and healthy controls were genotyped for the p.R122H mutation in the PRSS1 gene, p.N34S and IVS3 + 2T > C variants in the SPINK1 gene, the p.G191R variant in the anionic trypsinogen gene, the p.E32del variant in the mesotrypsinogen (PRSS3) gene, and the -2518G > A variant in the monocyte chemoattractant protein-1 gene by polymerase chain reaction-restriction enzyme digestion and direct sequencing.