Japanese Clinical Guidelines 2020 for Diagnosis and Treatment of Juvenile polyposis syndrome in Children and Adults

Abstract

Juvenile polyposis syndrome (JPS) is a rare disease characterized by multiple hamartomatous polyps within the gastrointestinal tract. It is caused by germline pathogenic variants of the SMAD4 or BMPR1A. Approximately 75% of newly diagnosed cases have an autosomal-dominantly inherited condition, whereas 25% are sporadic without previous history of polyposis in the family pedigree. CS/PHTS may be identified by multigene panel testing in patients with cancer. JPS is classified into three categories according to phenotypic features of polyp distribution. These include generalized juvenile polyposis, juvenile polyposis coli, and juvenile polyposis of the stomach. Juvenile polyposis of the stomach is caused by germline pathogenic variants of SMAD4 with a high risk for the development of gastric cancer. Pathogenic variant of SMAD4 is also associated with hereditary hemorrhagic telangiectasia-JPS complex, which needs regular survey for cardiovascular system. The present clinical guidelines explain the principles in the diagnosis and management of JPS, together with three clinical questions and corresponding recommendations. The guidelines have been designed to promote seamless implementation of accurate diagnosis and appropriate management of pediatric, adolescent and adult patients with the disease.