G-Protein-Coupled Receptor Class C Group 6 Member A (GPRC6A) and Serine Protease Inhibitor, Kazal Type 1 (SPINK1) Genotypes Associated With Refractory Functional Dyspepsia: A Potential Link to Endosonographic Features.

BACKGROUND

This study aims to determine the associations between single-nucleotide polymorphisms (SNPs) in G-protein-coupled receptor class C group 6 member A​​​​​​​ (GPRC6A) and serine protease inhibitor, Kazal type 1 (SPINK1) genes and the clinical characteristics, including clinical symptoms, pancreatic enzyme abnormalities, and exocrine pancreatic function, with refractory functional dyspepsia (R-FD).

METHODS

Around 97 patients with FD and 74 R-FD were recruited. Five pancreatic enzymes were measured. DNA was isolated from blood or duodenal tissues. Endoscopic ultrasonography (EUS) was performed using Olympus EUS (GF-UCT 260; Olympus, Tokyo, Japan) under conscious sedation in patients with R-FD. Exocrine or endocrine pancreatic function was estimated.

RESULTS

Significant differences (p < 0.001) were observed in the ratio of abnormal pancreatic enzyme levels between patients with R-FD and those with FD. However, no significant differences in the distribution of GPRC6A and SPINK1 genotypes were observed in the FD and R-FD groups. EUS score in the GG genotype was significantly higher than in the CC or CG genotypes (p = 0.036 and p = 0.031, respectively) in GPRC6A in R-FD. In addition, the lobularity in GG genotype in GPRC6A in R-FD was also significantly higher (p = 0.023 and p = 0.027, respectively) than that in CC or CG.

CONCLUSION

Significant differences (p < 0.001) were observed in the ratio of abnormal pancreatic enzyme levels between patients with R-FD and those with FD. GPRC6A genotype was significantly associated with EUS features, and further studies will be needed to clarify the significant association between GPRC6A genotype and EUS score.