Hereditary mixed polyposis syndrome (HMPS) [OMIM#601228] is a rare condition characterized by the development of colorectal polyps with multiple, mixed morphologies, and increased risk of colorectal cancer. Polyp types observed in affected individuals include serrated lesions, Peutz-Jeghers polyps, juvenile polyps and conventional adenomas. Jaeger et al. (2012) identified a heterozygous 40-kb duplication at 15q13.3 that extended from intron 2 of the SCG5 gene to a site upstream of the GREM1 locus and just upstream of the CpG island of the GREM1 gene, [OMIM#603054], in multiple families of Ashkenazi Jewish descent with HMPS. There was perfect concordance between the presence of the duplication and affected status in the families studied. The duplication was not identified in any control patients, and was only identified in individuals of Ashkenazi Jewish descent, suggesting this is a founder mutation in this population. We offer targeted testing for the duplication that has been identified in Ashkenazi Jewish individuals with HMPS.
Specimen Types Accepted