Novel mutation and polymorphism of PRSS1 gene in the Chinese patients with hereditary pancreatitis and chronic pancreatitis

BACKGROUND: Mutations in the cationic trypsinogen gene (PRSS1) have been detected in patients with hereditary pancreatitis (HP). This study investigated the prevalence of the R122H (c.365 G > A), A121T (c.361 G > A) and D162D (c.488 C > T) mutations or polymorphisms in the common, non-hereditary forms of chronic pancreatitis and in an HP family. METHODS: DNA was prepared from blood samples of 54 patients with chronic pancreatitis (35 alcoholic, 17 idiopathic and 2 hereditary) and 120 normal controls. The PRSS1 genes were amplified by polymerase chain reaction (PCR) and their products were analyzed by sequencing and related clinical data were also collected. RESULTS: A new polymorphism (c.488 C > T) of PRSS1 was found in 25 patients with chronic pancreatitis (including one affected member of the HP family) and six members of the normal controls. The C/T genotype was significantly increased in chronic pancreatitis (OR: 16.379, 95% CI: 5.7522 - 52.3663), the frequency of c.488 C > T change was in according with the Hardy-Weinberg equilibrium, but it doesn't affect the clinical phenotype. The commonly reported change of R122H (c.365 G > A) was not detected in any of the study subjects. c.361 G > A was found in 2 affected members and one unaffected carrier in an HP family. One of the affected members of an HP family had c.361 G > A mutation and polymorphism (c.488 C > T) in the PRSS1 gene at the same time. The patient's clinical values (C3, C4, CA19-9 and HbA1c) were higher than those of the other patients with chronic pancreatitis. The two patients with HP developed diabetes mellitus and their father died with pancreatic cancer. CONCLUSION: A new polymorphism (c.488 C > T) in the PRSS1 gene is associated with chronic pancreatitis, but it did not affect the clinical phenotype while the A121T (c.361 G > A) mutation in the gene shows a significant correlation in the patients with HP.