We read with interest the above article by Goldberg et al that described patients from 4 Ashkenazi Jewish families with a 40-kb duplication upstream of GREM1.1 The authors presented the clinical manifestation of these patients classified as hereditary mixed polyposis syndrome (HMPS) (Table 1) and surmised that GREM1 should be included in gene panel testing for patients of any ancestry with inherited polyposis and hereditary colorectal cancer, including familial adenomatous polyposis (FAP) or the Lynch syndrome.