Caring for someone with this diagnosis? Eleplan keeps diagnoses, medications, documents and every specialist in one plan.
Start free with EleplanMalan overgrowth syndrome
ORPHA:420179Malformation syndrome
Also called Sotos syndrome 2
What it is
A rare multisystemic genetic disorder characterized by a characteristic facial features with macrocephaly, overgrowth in infancy, intellectual disability and behavioral problems including anxieties and aggressiveness.
Key facts
- Prevalence
- <1 / 1 000 000
- Age of onset
- Infancy
- Inheritance
- Autosomal dominant, 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
Common30–79%
16- Downslanted palpebral fissures
- Feeding difficulties in infancy
- High forehead
- Hypoplasia of the corpus callosum
- Intellectual disability, moderate
- Low posterior hairline
- Macrocephaly
- Narrow face
- Neonatal hypotonia
- Oval face
- Pectus excavatum
- Prominent forehead
- Slender long bone
- Strabismus
- Tall stature
- Ventriculomegaly
Sometimes5–29%
21- Anxiety
- Deeply set eye
- Depressed nasal bridge
- Episodic ataxia
- Facial asymmetry
- Frontal bossing
- High palate
- Hypoplasia of the brainstem
and 13 more in this range
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.
Powered by Eleplan
A rare diagnosis is just the start. Eleplan keeps the whole care plan in one place.
Diagnoses, medications, documents, appointments, and the whole care team — organized and always in sync, so you are not retelling the same story to every new specialist. With Ellie, your AI care assistant, on top of it. Free to start.