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Start free with Eleplan9q33.3q34.11 microdeletion syndrome
ORPHA:495818Malformation syndrome
Also called Del(9)(q33.3q34.11) · Deletion 9q33.3q34.11 · Monosomy 9q33.3q34.11
What it is
A partial monosomy of the long arm of chromosome 9 characterized by intellectual disability, developmental delay with pronounced speech delay, short stature, and muscular hypotonia. Common craniofacial dysmorphic features consist of microcephaly, prominent forehead, round face, arched eyebrows, upslanting palpebral fissures, strabismus, short nose, and thin upper lip. Other clinical findings include epilepsy, ataxia, unspecific brain MRI findings, early-onset primary dystonia, nail dysplasia, and bone malformations, in particular patellar abnormalities, epistaxis, and cutaneous-mucous telangiectasias.
Key facts
- Prevalence
- <1 / 1 000 000
- Age of onset
- Childhood, Infancy
- Inheritance
- Not applicable
- Classified as
- Malformation syndrome
Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.
Signs and symptoms
Very common80–99%
15Common30–79%
17These ranges are how often a sign appears across everyone diagnosed, not a prediction for one person — most people have some of these and not others. Orphanet also records findings that are specifically absent in this disease; those are in the data but not listed here.
Genes
ICD-10 codes
ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.
Related health topics
Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.
Cross-references
Orphadata Science: Free access data from Orphanet. © INSERM 1999. Data version 2026-06-23. Available under CC BY 4.0. This is a reference, not medical advice.
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