Synonyms: Del(12)(p12.1) | Monosomy 12p12.1
A rare chromosomal anomaly syndrome resulting from the partial deletion of the short arm of chromosome 12 characterized by intellectual disability global developmental delay with prominent language impairment behavioral abnormalities and mild facial dysmorphism (incl. frontal bossing downslanting palpebral fissures epicanthal folds broad depressed nasal bridge with bulbous nasal tip low-set ears with underdeveloped helices). Other associated features may include skeletal abnormalities (butterfly vertebrae scoliosis) strabismus optic nerve hypoplasia and brain malformations.
Data from Orphanet are used to provide information on a disease's name, synonym(s), and overview. Reference: Access aggregated data from Orphanet at Orphadata. Orphadata: Free access data from Orphanet. © INSERM 1999. Available on http://www.orphadata.org. Data version July 2026
Newly diagnosed with
12p12.1 microdeletion syndrome?
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Advocacy Organizations
PPP2CA Pathways
PPP2CA Pathways connects families, shares strength, and supports the research community in the search for answers to Houge-Janssens Syndrome type 3.
Rare Chromosome Disorder Support Group – Unique
Through sharing knowledge and lived experience, Unique helps families and professionals navigate the world of chromosome and gene disorders
ReNU2 Foundation
ReNU2 Foundation supports families affected by RNU2-2-related neurodevelopmental disease. We foster collaboration, raise awareness, and advance research—pursuing a world where every family has testing, informed care, community, and treatment.
Uganda Alliance of Patients Organization
Supporting patients to access quality, safe and patient-centered healthcare services.
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Clinical Trials
For a list of clinical trials in this disease area, please click here.