Absence of motilin gene mutations in infantile hypertrophic pyloric stenosis.

BACKGROUND: Erythromycin treatment before 2 weeks of age has been shown to increase the risk of infantile hypertrophic pyloric stenosis (IHPS) up to 10 times. Erythromycin is a motilin agonist, a hormone that induces gastrointestinal contractions. The purpose of this study was to investigate if mutations in the motilin gene (MLN) cause IHPS or if the V15A polymorphism in MLN is associated with the disease.

METHODS: The MLN was screened for mutations, and the V15A polymorphism was determined in a total of 57 patients with IHPS using polymerase chain reaction and DNA sequencing. The polymorphism genotype and allele frequencies among the patients were compared with 184 controls.

RESULTS: We detected 3 different, not previously reported, MLN sequence variants in 4 patients. One of these variants results in an amino acid exchange in the motilin signal peptide (A25G). All 3 detected sequence variants were also found in controls or were not inherited with the disease. We found no significant association between the V15A polymorphism and the disease.

CONCLUSIONS: We have excluded the MLN coding region as a major cause of IHPS. Future studies will evaluate the importance of this metabolic pathway in the pathogenesis of IHPS.