{"id":170,"date":"2011-06-10T18:50:17","date_gmt":"2011-06-10T18:50:17","guid":{"rendered":"http:\/\/stg-blogs.bmj.com\/jmg\/?p=170"},"modified":"2011-06-10T18:50:17","modified_gmt":"2011-06-10T18:50:17","slug":"detection-of-apc-germ-line-mosaicism-in-patients-with-de-novo-familial-adenomatous-polyposis-a-plea-for-the-ptt-2","status":"publish","type":"post","link":"https:\/\/stg-blogs.bmj.com\/jmg\/2011\/06\/10\/detection-of-apc-germ-line-mosaicism-in-patients-with-de-novo-familial-adenomatous-polyposis-a-plea-for-the-ptt-2\/","title":{"rendered":"Detection of APC germ line mosaicism in patients with de novo familial adenomatous polyposis: a plea for the PTT"},"content":{"rendered":"<p>Current recommendations for <em>APC<\/em> mutation analysis in patients with familial adenomatous polyposis (FAP) advise full gene sequencing and gene dosage analysis replacing the protein truncation test (PTT) as a pre-screening tool. Here we report on two unrelated patients with classical FAP and unremarkable family history in whose leukocyte-derived DNA no pathogenic <em>APC<\/em> mutations could be identified. PTT analysis, however, evidenced aberrant bands in both patients with subsequent targeted mutation analysis of their tumour-derived DNA identifying two novel, pathogenic <em>APC<\/em> alterations present in a mosaic state, at blood levels (1 \u2013 15%) below the detection limits of conventional Sanger sequencing. Our findings demonstrate the value of the PTT to identify mosaic mutations in apparently <em>APC<\/em> mutation-negative FAP patients with <em>de novo<\/em> classical polyposis and the need to keep the PTT within the diagnostic repertoire for <em>APC<\/em> mutation analysis. (By Karl Heinimann, <a href=\"http:\/\/jmg.bmj.com\/content\/early\/2011\/06\/10\/jmg.2011.089474.abstract?papetoc\">http:\/\/jmg.bmj.com\/content\/early\/2011\/06\/10\/jmg.2011.089474.abstract?papetoc<\/a> )<!--TrendMD v2.4.8--><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Current recommendations for APC mutation analysis in patients with familial adenomatous polyposis (FAP) advise full gene sequencing and gene dosage analysis replacing the protein truncation test (PTT) as a pre-screening tool. Here we report on two unrelated patients with classical FAP and unremarkable family history in whose leukocyte-derived DNA no pathogenic APC mutations could be [&#8230;]<\/p>\n<p><a class=\"btn btn-secondary understrap-read-more-link\" href=\"https:\/\/stg-blogs.bmj.com\/jmg\/2011\/06\/10\/detection-of-apc-germ-line-mosaicism-in-patients-with-de-novo-familial-adenomatous-polyposis-a-plea-for-the-ptt-2\/\">Read More&#8230;<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[1],"tags":[],"class_list":["post-170","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/stg-blogs.bmj.com\/jmg\/wp-json\/wp\/v2\/posts\/170","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/stg-blogs.bmj.com\/jmg\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/stg-blogs.bmj.com\/jmg\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/stg-blogs.bmj.com\/jmg\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/stg-blogs.bmj.com\/jmg\/wp-json\/wp\/v2\/comments?post=170"}],"version-history":[{"count":0,"href":"https:\/\/stg-blogs.bmj.com\/jmg\/wp-json\/wp\/v2\/posts\/170\/revisions"}],"wp:attachment":[{"href":"https:\/\/stg-blogs.bmj.com\/jmg\/wp-json\/wp\/v2\/media?parent=170"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/stg-blogs.bmj.com\/jmg\/wp-json\/wp\/v2\/categories?post=170"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/stg-blogs.bmj.com\/jmg\/wp-json\/wp\/v2\/tags?post=170"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}