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Start free with Eleplan2q23.1 microdeletion syndrome
ORPHA:228402Malformation syndrome
Also called Del(2)(q23.1) · Monosomy 2q23.1 · Pseudo-Angelman syndrome
What it is
The newly described 2q23.1 microdeletion syndrome includes severe intellectual deficit with pronounced speech delay, behavioral abnormalities including hyperactivity and inappropriate laughter, short stature and seizures.
Key facts
- Prevalence
- <1 / 1 000 000
- Age of onset
- Infancy, Neonatal
- Inheritance
- Not applicable, Unknown
- 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%
4Common30–79%
24- Ataxia
- Brachycephaly
- Broad forehead
- Clinodactyly of the 5th finger
- Coarse facial features
- Constipation
- Everted lower lip vermilion
- Generalized hirsutism
- Growth delay
- Highly arched eyebrow
- Hyperactivity
- Hypotonia
- Malar flattening
- Microcephaly
- Open mouth
- Paroxysmal bursts of laughter
- Polyphagia
- Sandal gap
- Self-injurious behavior
- Short palm
- Short stature
- Sleep abnormality
- Synophrys
- Tented upper lip vermilion
These 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.
Gene
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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