{"id":86042,"date":"2024-11-14T14:07:30","date_gmt":"2024-11-14T05:07:30","guid":{"rendered":"https:\/\/www.hiro-clinic.or.jp\/nipt\/4q21_deletion_syndrome\/"},"modified":"2026-07-12T21:26:27","modified_gmt":"2026-07-12T12:26:27","slug":"4q21_deletion_syndrome","status":"publish","type":"post","link":"https:\/\/www.hiro-clinic.or.jp\/nipt\/4q21_deletion_syndrome\/?lang=en","title":{"rendered":"4q21 Deletion Syndrome"},"content":{"rendered":"\n

If a chromosomal test or a prenatal screening result mentioned “4q21 deletion syndrome,” it’s natural to feel uneasy about a term you’re hearing for the first time.<\/strong><\/p>\n\n\n\n

Here is the short answer. 4q21 deletion syndrome is a chromosomal condition caused by a congenital loss of part of the long arm of chromosome 4, in the q21 region, and only a very small number of cases have been reported worldwide.<\/strong> The features reported most often include growth delay, low muscle tone (hypotonia), delayed or absent speech development, and a distinctive facial appearance.<\/p>\n\n\n\n

This article walks through the chromosomal change and the genes involved, the difference from the often-confused “distal 4q deletion syndrome,” the main symptoms reported in the literature, the inheritance pattern, the relationship with prenatal diagnosis and NIPT<\/a>, the path to a confirmed diagnosis, and treatment and outlook. We draw on public and academic sources such as GARD (the U.S. National Institutes of Health’s Genetic and Rare Diseases Information Center) and peer-reviewed papers. Because reliable information on this rare condition is limited, let’s go through it one point at a time.<\/p>\n\n\n\n

\n

\ud83d\udca1 What this article covers<\/p>\n