Genetic polymorphisms of SCN10A are associated with functional dyspepsia in Japanese subjects

Background: Visceral sensory impulses are transmitted via C-fibers from the gastrointestinal tract to the central nervous system. The tetrodotoxinresistant (TTX-r) sodium channel, Na(V) 1.8/SNS (sensory-neuron specific), encoded by SCN10A, has been identified on C-fibers. We attempted to clarify the association between functional dyspepsia (FD) and SCN10A non-synonymous polymorphisms (2884 A>G, 3218 C>T and 3275 T>C). Methods: The study was performed in 642 subjects (345 with no symptoms and 297 with FD). We employed a multiplex polymerase chain reaction single-strand confirmation polymorphism (PCR-SSCP) method to detect the gene polymorphisms. Results: The 3218 CC homozygotes had a reduced risk for the development of FD [odds ratio (OR) 0.589; 95 % confidence interval (CI) 0.402-0.864; p = 0.0067]. In addition, both 2884 A>G and 3275 T>C, which were in linkage disequilibrium, were also associated with the development of FD (p = 0.039 and 0.028, respectively). Each 2884 G carrier, 3218 CC homozygote, and 3275 C carrier had a reduced risk for the development of both epigastric pain syndrome (EPS) and postprandial distress syndrome (PDS). The subjects with the 2884 G allele, 3275 C allele, and no 3218 T allele had a reduced risk for FD (OR 0.618; 95 % CI 0.448-0.853; p = 0.0034). This haplotype was associated with a reduced risk for both EPS and PDS (p = 0.0011 and 0.0056, respectively). In addition, there was a significant association between FD and this haplotype in Helicobacter pylori-negative subjects (OR 0.463; 95 % CI 0279-0.9768; p = 0.0029). Conclusion: We conclude that genetic polymorphisms of SCN10A are closely associated with FD (both EPS and PDS), especially in H. pylori-negative subjects, in Japanese.