{"id":170,"date":"2011-06-10T18:50:17","date_gmt":"2011-06-10T18:50:17","guid":{"rendered":"https:\/\/blogs.bmj.com\/jmg\/?p=170"},"modified":"2026-02-25T20:59:14","modified_gmt":"2026-02-25T20:59:14","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:\/\/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 (Contributed by Karl Heinimann)"},"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. (<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:\/\/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":123,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-170","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.4 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Detection of APC germ line mosaicism in patients with de novo familial adenomatous polyposis: a plea for the PTT (Contributed by Karl Heinimann) - JMG Contact blog<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/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\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Detection of APC germ line mosaicism in patients with de novo familial adenomatous polyposis: a plea for the PTT (Contributed by Karl Heinimann) - JMG Contact blog\" \/>\n<meta property=\"og:description\" content=\"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 [...]Read More...\" \/>\n<meta property=\"og:url\" content=\"https:\/\/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\/\" \/>\n<meta property=\"og:site_name\" content=\"JMG Contact blog\" \/>\n<meta property=\"article:published_time\" content=\"2011-06-10T18:50:17+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2026-02-25T20:59:14+00:00\" \/>\n<meta name=\"author\" content=\"hqqu\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:creator\" content=\"@HuiQiQu\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"hqqu\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"1 minute\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/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\\\/#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/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\\\/\"},\"author\":{\"name\":\"hqqu\",\"@id\":\"https:\\\/\\\/blogs.bmj.com\\\/jmg\\\/#\\\/schema\\\/person\\\/be0250f8d5b52412c3e7c222dabd591b\"},\"headline\":\"Detection of APC germ line mosaicism in patients with de novo familial adenomatous polyposis: a plea for the PTT (Contributed by Karl Heinimann)\",\"datePublished\":\"2011-06-10T18:50:17+00:00\",\"dateModified\":\"2026-02-25T20:59:14+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\\\/\\\/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\\\/\"},\"wordCount\":166,\"commentCount\":0,\"publisher\":{\"@id\":\"https:\\\/\\\/blogs.bmj.com\\\/jmg\\\/#organization\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\\\/\\\/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\\\/#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/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\\\/\",\"url\":\"https:\\\/\\\/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\\\/\",\"name\":\"Detection of APC germ line mosaicism in patients with de novo familial adenomatous polyposis: a plea for the PTT (Contributed by Karl Heinimann) - JMG Contact blog\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/blogs.bmj.com\\\/jmg\\\/#website\"},\"datePublished\":\"2011-06-10T18:50:17+00:00\",\"dateModified\":\"2026-02-25T20:59:14+00:00\",\"breadcrumb\":{\"@id\":\"https:\\\/\\\/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\\\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\\\/\\\/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\\\/\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/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\\\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\\\/\\\/blogs.bmj.com\\\/jmg\\\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Detection of APC germ line mosaicism in patients with de novo familial adenomatous polyposis: a plea for the PTT (Contributed by Karl Heinimann)\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/blogs.bmj.com\\\/jmg\\\/#website\",\"url\":\"https:\\\/\\\/blogs.bmj.com\\\/jmg\\\/\",\"name\":\"JMG Contact blog\",\"description\":\"JMG Contact blog\",\"publisher\":{\"@id\":\"https:\\\/\\\/blogs.bmj.com\\\/jmg\\\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\\\/\\\/blogs.bmj.com\\\/jmg\\\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Organization\",\"@id\":\"https:\\\/\\\/blogs.bmj.com\\\/jmg\\\/#organization\",\"name\":\"JMG Contact blog\",\"url\":\"https:\\\/\\\/blogs.bmj.com\\\/jmg\\\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/blogs.bmj.com\\\/jmg\\\/#\\\/schema\\\/logo\\\/image\\\/\",\"url\":\"https:\\\/\\\/blogs.bmj.com\\\/jmg\\\/files\\\/2017\\\/10\\\/blog-logo-jmg.png\",\"contentUrl\":\"https:\\\/\\\/blogs.bmj.com\\\/jmg\\\/files\\\/2017\\\/10\\\/blog-logo-jmg.png\",\"width\":300,\"height\":34,\"caption\":\"JMG Contact blog\"},\"image\":{\"@id\":\"https:\\\/\\\/blogs.bmj.com\\\/jmg\\\/#\\\/schema\\\/logo\\\/image\\\/\"}},{\"@type\":\"Person\",\"@id\":\"https:\\\/\\\/blogs.bmj.com\\\/jmg\\\/#\\\/schema\\\/person\\\/be0250f8d5b52412c3e7c222dabd591b\",\"name\":\"hqqu\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/920bc4e81500cde88def4bfd7775029cb154e422c5460b9cf80d5c47137d6f35?s=96&d=mm&r=g\",\"url\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/920bc4e81500cde88def4bfd7775029cb154e422c5460b9cf80d5c47137d6f35?s=96&d=mm&r=g\",\"contentUrl\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/920bc4e81500cde88def4bfd7775029cb154e422c5460b9cf80d5c47137d6f35?s=96&d=mm&r=g\",\"caption\":\"hqqu\"},\"description\":\"Huiqi Qu has a background as a physician trained in internal medicine and a PhD in Experimental Medicine (Endocrinology). His research applies human genetics and multi-omics to complex and pediatric diseases, including GWAS, polygenic risk scores (PRS), single-cell transcriptomics, and integrative genomics to support precision medicine and clinical translation.\",\"sameAs\":[\"https:\\\/\\\/x.com\\\/HuiQiQu\"],\"url\":\"https:\\\/\\\/blogs.bmj.com\\\/jmg\\\/author\\\/hqiqu\\\/\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Detection of APC germ line mosaicism in patients with de novo familial adenomatous polyposis: a plea for the PTT (Contributed by Karl Heinimann) - JMG Contact blog","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/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\/","og_locale":"en_US","og_type":"article","og_title":"Detection of APC germ line mosaicism in patients with de novo familial adenomatous polyposis: a plea for the PTT (Contributed by Karl Heinimann) - JMG Contact blog","og_description":"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 [...]Read More...","og_url":"https:\/\/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\/","og_site_name":"JMG Contact blog","article_published_time":"2011-06-10T18:50:17+00:00","article_modified_time":"2026-02-25T20:59:14+00:00","author":"hqqu","twitter_card":"summary_large_image","twitter_creator":"@HuiQiQu","twitter_misc":{"Written by":"hqqu","Est. reading time":"1 minute"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/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\/#article","isPartOf":{"@id":"https:\/\/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\/"},"author":{"name":"hqqu","@id":"https:\/\/blogs.bmj.com\/jmg\/#\/schema\/person\/be0250f8d5b52412c3e7c222dabd591b"},"headline":"Detection of APC germ line mosaicism in patients with de novo familial adenomatous polyposis: a plea for the PTT (Contributed by Karl Heinimann)","datePublished":"2011-06-10T18:50:17+00:00","dateModified":"2026-02-25T20:59:14+00:00","mainEntityOfPage":{"@id":"https:\/\/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\/"},"wordCount":166,"commentCount":0,"publisher":{"@id":"https:\/\/blogs.bmj.com\/jmg\/#organization"},"inLanguage":"en-US","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/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\/#respond"]}]},{"@type":"WebPage","@id":"https:\/\/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\/","url":"https:\/\/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\/","name":"Detection of APC germ line mosaicism in patients with de novo familial adenomatous polyposis: a plea for the PTT (Contributed by Karl Heinimann) - JMG Contact blog","isPartOf":{"@id":"https:\/\/blogs.bmj.com\/jmg\/#website"},"datePublished":"2011-06-10T18:50:17+00:00","dateModified":"2026-02-25T20:59:14+00:00","breadcrumb":{"@id":"https:\/\/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\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/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\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/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\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/blogs.bmj.com\/jmg\/"},{"@type":"ListItem","position":2,"name":"Detection of APC germ line mosaicism in patients with de novo familial adenomatous polyposis: a plea for the PTT (Contributed by Karl Heinimann)"}]},{"@type":"WebSite","@id":"https:\/\/blogs.bmj.com\/jmg\/#website","url":"https:\/\/blogs.bmj.com\/jmg\/","name":"JMG Contact blog","description":"JMG Contact blog","publisher":{"@id":"https:\/\/blogs.bmj.com\/jmg\/#organization"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/blogs.bmj.com\/jmg\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Organization","@id":"https:\/\/blogs.bmj.com\/jmg\/#organization","name":"JMG Contact blog","url":"https:\/\/blogs.bmj.com\/jmg\/","logo":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/blogs.bmj.com\/jmg\/#\/schema\/logo\/image\/","url":"https:\/\/blogs.bmj.com\/jmg\/files\/2017\/10\/blog-logo-jmg.png","contentUrl":"https:\/\/blogs.bmj.com\/jmg\/files\/2017\/10\/blog-logo-jmg.png","width":300,"height":34,"caption":"JMG Contact blog"},"image":{"@id":"https:\/\/blogs.bmj.com\/jmg\/#\/schema\/logo\/image\/"}},{"@type":"Person","@id":"https:\/\/blogs.bmj.com\/jmg\/#\/schema\/person\/be0250f8d5b52412c3e7c222dabd591b","name":"hqqu","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/secure.gravatar.com\/avatar\/920bc4e81500cde88def4bfd7775029cb154e422c5460b9cf80d5c47137d6f35?s=96&d=mm&r=g","url":"https:\/\/secure.gravatar.com\/avatar\/920bc4e81500cde88def4bfd7775029cb154e422c5460b9cf80d5c47137d6f35?s=96&d=mm&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/920bc4e81500cde88def4bfd7775029cb154e422c5460b9cf80d5c47137d6f35?s=96&d=mm&r=g","caption":"hqqu"},"description":"Huiqi Qu has a background as a physician trained in internal medicine and a PhD in Experimental Medicine (Endocrinology). His research applies human genetics and multi-omics to complex and pediatric diseases, including GWAS, polygenic risk scores (PRS), single-cell transcriptomics, and integrative genomics to support precision medicine and clinical translation.","sameAs":["https:\/\/x.com\/HuiQiQu"],"url":"https:\/\/blogs.bmj.com\/jmg\/author\/hqiqu\/"}]}},"_links":{"self":[{"href":"https:\/\/blogs.bmj.com\/jmg\/wp-json\/wp\/v2\/posts\/170","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.bmj.com\/jmg\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.bmj.com\/jmg\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.bmj.com\/jmg\/wp-json\/wp\/v2\/users\/123"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.bmj.com\/jmg\/wp-json\/wp\/v2\/comments?post=170"}],"version-history":[{"count":0,"href":"https:\/\/blogs.bmj.com\/jmg\/wp-json\/wp\/v2\/posts\/170\/revisions"}],"wp:attachment":[{"href":"https:\/\/blogs.bmj.com\/jmg\/wp-json\/wp\/v2\/media?parent=170"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.bmj.com\/jmg\/wp-json\/wp\/v2\/categories?post=170"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.bmj.com\/jmg\/wp-json\/wp\/v2\/tags?post=170"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}