{"id":2139,"date":"2026-01-19T14:47:03","date_gmt":"2026-01-19T14:47:03","guid":{"rendered":"https:\/\/blogs.bmj.com\/jmg\/?p=2139"},"modified":"2026-02-22T00:12:01","modified_gmt":"2026-02-22T00:12:01","slug":"biallelic-ttbk1-variant-causes-a-severe-syndromic-neurodevelopmental-disorder-clinical-and-genetic-insights-from-two-siblings","status":"publish","type":"post","link":"https:\/\/blogs.bmj.com\/jmg\/2026\/01\/19\/biallelic-ttbk1-variant-causes-a-severe-syndromic-neurodevelopmental-disorder-clinical-and-genetic-insights-from-two-siblings\/","title":{"rendered":"Biallelic TTBK1 variant causes a severe syndromic neurodevelopmental disorder: clinical and genetic insights from two siblings (Contributed by Zehra Manav Yigit, MD)"},"content":{"rendered":"

Rare genetic conditions affecting brain development are often difficult to diagnose, especially when the responsible gene has previously been studied only in adult brain diseases. In this study, we describe two siblings with a severe neurodevelopmental disorder caused by a loss-of-function change in the\u00a0TTBK1\u00a0<\/em>gene.\u00a0TTBK1\u00a0<\/em>is best known for its role in Alzheimer\u2019s disease and other neurodegenerative conditions, but its importance during early brain development has been unclear. Our findings provide the first human evidence that\u00a0TTBK1\u00a0<\/em>is essential for normal motor and cognitive development. This work expands the list of genes causing childhood neurodevelopmental disorders and highlights how genes linked to adult brain diseases can also play critical roles early in life. (https:\/\/jmg.bmj.com\/content\/early\/2026\/01\/15\/jmg-2025-111208<\/a> )<\/p>\n","protected":false},"excerpt":{"rendered":"

Rare genetic conditions affecting brain development are often difficult to diagnose, especially when the responsible gene has previously been studied only in adult brain diseases. In this study, we describe two siblings with a severe neurodevelopmental disorder caused by a loss-of-function change in the\u00a0TTBK1\u00a0gene.\u00a0TTBK1\u00a0is best known for its role in Alzheimer\u2019s disease and other neurodegenerative […]<\/p>\n

Read More…<\/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-2139","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"yoast_head":"\nBiallelic TTBK1 variant causes a severe syndromic neurodevelopmental disorder: clinical and genetic insights from two siblings (Contributed by Zehra Manav Yigit, MD) - 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\/2026\/01\/19\/biallelic-ttbk1-variant-causes-a-severe-syndromic-neurodevelopmental-disorder-clinical-and-genetic-insights-from-two-siblings\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Biallelic TTBK1 variant causes a severe syndromic neurodevelopmental disorder: clinical and genetic insights from two siblings (Contributed by Zehra Manav Yigit, MD) - JMG Contact blog\" \/>\n<meta property=\"og:description\" content=\"Rare genetic conditions affecting brain development are often difficult to diagnose, especially when the responsible gene has previously been studied only in adult brain diseases. In this study, we describe two siblings with a severe neurodevelopmental disorder caused by a loss-of-function change in the\u00a0TTBK1\u00a0gene.\u00a0TTBK1\u00a0is best known for its role in Alzheimer\u2019s disease and other neurodegenerative [...]Read More...\" \/>\n<meta property=\"og:url\" content=\"https:\/\/blogs.bmj.com\/jmg\/2026\/01\/19\/biallelic-ttbk1-variant-causes-a-severe-syndromic-neurodevelopmental-disorder-clinical-and-genetic-insights-from-two-siblings\/\" \/>\n<meta property=\"og:site_name\" content=\"JMG Contact blog\" \/>\n<meta property=\"article:published_time\" content=\"2026-01-19T14:47:03+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2026-02-22T00:12:01+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\\\/2026\\\/01\\\/19\\\/biallelic-ttbk1-variant-causes-a-severe-syndromic-neurodevelopmental-disorder-clinical-and-genetic-insights-from-two-siblings\\\/#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/blogs.bmj.com\\\/jmg\\\/2026\\\/01\\\/19\\\/biallelic-ttbk1-variant-causes-a-severe-syndromic-neurodevelopmental-disorder-clinical-and-genetic-insights-from-two-siblings\\\/\"},\"author\":{\"name\":\"hqqu\",\"@id\":\"https:\\\/\\\/blogs.bmj.com\\\/jmg\\\/#\\\/schema\\\/person\\\/be0250f8d5b52412c3e7c222dabd591b\"},\"headline\":\"Biallelic TTBK1 variant causes a severe syndromic neurodevelopmental disorder: clinical and genetic insights from two siblings (Contributed by Zehra Manav Yigit, MD)\",\"datePublished\":\"2026-01-19T14:47:03+00:00\",\"dateModified\":\"2026-02-22T00:12:01+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\\\/\\\/blogs.bmj.com\\\/jmg\\\/2026\\\/01\\\/19\\\/biallelic-ttbk1-variant-causes-a-severe-syndromic-neurodevelopmental-disorder-clinical-and-genetic-insights-from-two-siblings\\\/\"},\"wordCount\":146,\"commentCount\":0,\"publisher\":{\"@id\":\"https:\\\/\\\/blogs.bmj.com\\\/jmg\\\/#organization\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"CommentAction\",\"name\":\"Comment\",\"target\":[\"https:\\\/\\\/blogs.bmj.com\\\/jmg\\\/2026\\\/01\\\/19\\\/biallelic-ttbk1-variant-causes-a-severe-syndromic-neurodevelopmental-disorder-clinical-and-genetic-insights-from-two-siblings\\\/#respond\"]}]},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/blogs.bmj.com\\\/jmg\\\/2026\\\/01\\\/19\\\/biallelic-ttbk1-variant-causes-a-severe-syndromic-neurodevelopmental-disorder-clinical-and-genetic-insights-from-two-siblings\\\/\",\"url\":\"https:\\\/\\\/blogs.bmj.com\\\/jmg\\\/2026\\\/01\\\/19\\\/biallelic-ttbk1-variant-causes-a-severe-syndromic-neurodevelopmental-disorder-clinical-and-genetic-insights-from-two-siblings\\\/\",\"name\":\"Biallelic TTBK1 variant causes a severe syndromic neurodevelopmental disorder: clinical and genetic insights from two siblings (Contributed by Zehra Manav Yigit, MD) - 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