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Start free with EleplanHouge-Janssens syndrome type 2
ORPHA:457284Clinical subtype
Also called HJS2 · PPP2R1A-related neurodevelopmental disorder · PPP2R1A-related Houge-Janssens syndrome
What it is
A rare genetic multiple congenital anomalies/dysmorphic syndrome characterized by variable degrees of developmental delay and intellectual disability with poor or absent speech, hypotonia, hypoplastic or absent corpus callosum, and facial dysmorphism (such as long face, frontal bossing, hypertelorism, downslanting palpebral fissures, and tented upper lip). Additional reported features include microcephaly, seizures, gait ataxia, scoliosis, and syndactyly of fingers, among others.
Key facts
- Prevalence
- <1 / 1 000 000
- Age of onset
- Infancy, Neonatal
- Inheritance
- Autosomal dominant
- Classified as
- Clinical subtype
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%
14Sometimes5–29%
22- Abnormal hair whorl
- Abnormality of the eye
- Anteverted nares
- Aplasia of the uterus
- Aplasia of the vagina
- Broad hallux
- Clinodactyly of the 5th finger
- Facial asymmetry
and 14 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.
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