Mutational analysis of the gene encoding the zymogen granule membrane glycoprotein 2 (GP2) in patients with chronic pancreatitis

Objectives: Premature activation of pancreatic digestive enzymes is considered as a major factor in the pathogenesis of pancreatitis. Genetic alterations of different pancreatic zymogens or their inhibitors have been associated with chronic pancreatitis (CP). Methods: We sequenced all 12 GP2 exons in 380 German CP patients and in 182 German control subjects. In addition, we analyzed exon 3 of GP2 in 803 further CP patients and 1780 controls originating from Germany, the Netherlands, and India by targeted DNA sequencing. Results: We detected 12 nonsynonymous and 6 synonymous exonic variants. All nonsynonymous changes with exception of c.220C>T (p.R74X) and c.502-503delG (p.G168fsX174) in exon 3 and c.541C>T (p.R181X) in exon 4 were missense mutations and predominantly located in exon 3. All nonsynonymous variants were found in single cases only, with exception of 2 alterations, c.355A>G (p.M119V) and c.409G>A (p. A137T), both located in exon 3. To elucidate the role of these 2 exon 3 variants, we investigated additional patients and controls. The frequency of these variants was similar between patients and controls regardless of ethnic background or cause of CP. Conclusions: Our data suggest that GP2 alterations do not alter the risk for the development of CP.