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Start free with EleplanMultiple congenital anomalies-hypotonia-seizures syndrome type 2
ORPHA:300496Malformation syndrome
Also called MCAHS type 2
What it is
A rare, genetic, lethal, neurometabolic malformation syndrome characterized by multiple, variable, congenital cardiac (systolic murmur, atrial septal defect), urinary (duplicated collecting system, vesicoureteral reflux) and central nervous system (thin corpus callosum, cerebellar hypoplasia) malformations associated with neonatal hypotonia, early-onset epileptic encephalopathy, and myoclonic seizures. Craniofacial dysmorphism (prominent occiput, enlarged fontanel, fused metopic suture, upslanted palpebral fissures, overfolded helix, depressed nasal bridge, anteverted nose, malar flattening, microstomy with downturned corners, Pierre-Robin sequence, high arched palate, short neck) and other manifestations (joint contractures, hyperreflexia, dysplastic nails, developmental delay) are also observed.
Key facts
- Prevalence
- <1 / 1 000 000
- Age of onset
- Antenatal, Infancy, Neonatal
- Inheritance
- X-linked recessive
- 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.
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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