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Start free with EleplanProximal Xq28 duplication syndrome
ORPHA:1762Malformation syndrome
Also called MECP2 duplication syndrome · X-linked intellectual disability syndrome, Lubs type
What it is
A rare X-linked genomic disorder associated with interstitial chromosomal duplications at Xq28 encompassing the MECP2 gene. It is characterized in males by infantile onset hypotonia, severe global developmental delay, intellectual disability, progressive spasticity, seizures, gastrointestinal symptoms and recurrent respiratory infections. In females, the phenotype is more variable.
Key facts
- Prevalence
- 1-9 / 1 000 000 (at birth, Australia)
- Age of onset
- Antenatal, Neonatal
- 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%
14- Abnormality of chromosome segregation
- Abnormality of speech or vocalization
- Blepharophimosis
- Cryptorchidism
- Delayed skeletal maturation
- Epicanthus
- Everted lower lip vermilion
- Global developmental delay
- Hypospadias
- Intellectual disability, severe
- Ptosis
- Severe global developmental delay
- Short stature
- 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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