{"id":85400,"date":"2024-11-14T14:25:03","date_gmt":"2024-11-14T05:25:03","guid":{"rendered":"https:\/\/www.hiro-clinic.or.jp\/nipt\/9p-deletion-syndrome\/"},"modified":"2026-07-12T21:22:49","modified_gmt":"2026-07-12T12:22:49","slug":"9p-deletion-syndrome","status":"publish","type":"post","link":"https:\/\/www.hiro-clinic.or.jp\/nipt\/9p-deletion-syndrome\/?lang=en","title":{"rendered":"9p Deletion Syndrome"},"content":{"rendered":"\n

You may have just been told your baby has been diagnosed with “9p Deletion Syndrome,” along with the unfamiliar term “trigonocephaly,” and are feeling overwhelmed.<\/strong><\/p>\n\n\n\n

Let’s start with the conclusion. 9p Deletion Syndrome is an extremely rare chromosomal disorder caused by a congenital loss of genetic material near the end of the short arm (p arm) of chromosome 9.<\/strong> First reported in 1973 and named after the reporting physician, it is also known as “Alfi syndrome.” Its two defining features are trigonocephaly \u2014 a forehead that appears pointed forward in a triangular shape \u2014 which often prompts diagnosis, and, depending on the size of the deletion, effects on sex differentiation (the process by which a baby’s sex characteristics form).<\/p>\n\n\n\n

This article walks through the chromosomal change that causes the condition, its symptoms, its effects on sex differentiation, how it differs from similarly named conditions, inheritance patterns, its relationship to prenatal testing and NIPT<\/a>, and treatment and family support options. All information is based on public institutions and peer-reviewed literature, so let’s go through it step by step rather than relying on fragmented information.<\/p>\n\n\n\n

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\ud83d\udca1 What This Article Covers<\/p>\n