obsolete_infantile hypertrophic pyloric stenosis true true http://purl.obolibrary.org/obo/MONDO_0001560 Replaced by Mondo term MONDO_0001560, with which this term was previously merged. Use: http://purl.obolibrary.org/obo/MONDO_0001560 3.88.0 This condition is caused by diffuse hypertrophy and hyperplasia of the smooth muscle of the antrum of the stomach and pylorus. It usually occurs in infants aged 2-8 weeks. The pyloric muscle hypertrophy results in narrowing of the pyloric canal, which can then become easily obstructed. Genetic studies have identified susceptibility loci for infantile hypertrophic pyloric stenosis (IHPS) and molecular studies have concluded that smooth muscle cells are not properly innervated in this condition. Panteli C; New insights into the pathogenesis of infantile pyloric stenosis. Pediatr Surg Int. 2009 Dec;25(12):1043-52. Epub 2009 Sep 16. [abstract] Helen Parkinson