Association between idiopathic achalasia and IL23R gene

Idiopathic achalasia is a primary esophageal motor disorder of unknown etiology. Different evidences have been reported in support of achalasia as the result of an autoimmune and inflammatory process leading to neuronal cell loss. According to this, idiopathic achalasia has been significantly associated with specific alleles of the human leukocyte antigen system class II, although few reports studying association with other loci can be found in the literature. Recent studies have shown association of a non-synonymous polymorphism within the IL23R gene with different chronic inflammatory disorders, including Barrett's esophagus. The purpose of this study was to assess whether the IL23R coding variant Arg381Gln polymorphism is involved in susceptibility to idiopathic achalasia.

We performed a case-control study including 262 patients with idiopathic achalasia and 802 healthy subjects, all of them white Spaniards. Achalasia patients were diagnosed on the basis of clinical, radiographic, endoscopic, and manometric criteria. All samples were genotyped for the IL23R Arg381Gln polymorphism using TaqMan technology.

The minor allele of the Arg381Gln polymorphism was significantly increased in patients compared with healthy controls (OR = 1.46, 95% CI = 1.01-2.11, P = 0.036). This association seems to be specific to male patients with disease onset after 40 years (OR = 2.33, 95% CI = 1.29-4.16, P = 0.002).

Our results suggest a role of IL23R in idiopathic achalasia predisposition and extend the evidence of the general influence of this gene in autoimmune and inflammatory diseases.