Molecular Genetics Juvenile Polyposis Syndrome (JPS), BMPR1A Sequencing

Juvenile polyposis syndrome is a rare (approximately 1 in 100,000 individuals), autosomal-dominant syndrome characterized by gastrointestinal polyps as well as an increased risk of colorectal cancer. Juvenile polyps are distinct in their hamartomatous nature and histology, in addition, juvenile polyps are commonly located in the colon and rectum. Mutations of BMPR1A as well as SMAD4 have been found in individuals affected with JPS. Most mutations of these mutations are small mutations (point mutations and small indels), with a smaller rate of larger aberrations impacting multiple exons or the entire gene. Small mutations of BMPR1A are identified in approximately 20% of JPS cases while larger aberrations are identified in approximately 2-11% of patients.

Reasons for Referral:

• Identification of inherited genetic defects in BMPR1A in patients with multiple juvenile polyps
• Confirmation of a suspected diagnosis with a positive family history of juvenile polyps when a familial mutation is known
• Predispositional testing for asymptomatic family members with a positive family history of juvenile polyps

For detailed information and ordering instructions, please refer to Full Gene Analysis (1240). Genes may be added or removed from the list below if clinically indicated.

 

1. Aretz S, et al. High proportion of large genomic deletions and a genotype-phenotype update in 80 unrelated families with juvenile polyposis syndrome.J Med Genet 2007; 44: 702-709.
2. Calva-Cerqueira D, et al. The rate of germline mutations and large deletions of SMAD4 and BMPR1A in juvenile polyposis. Clin Genet 2009: 79-85.
3. Howe, J et al. The prevalence of MADH4 and BMPR1A mutations in juvenile polyposis and absence of BMPR2, BMPR1B, and ACVR1 mutations. J Med Genet 2004; 41: 484-491.
4. van Hattem W, et al. Large genomic deletions of SMAD4, BMPR1A, and PTEN in juvenile polyposis. Gut 2008; 57: 623-627.