severe neonatal-onset encephalopathy with microcephaly
Findings
No curated finding names severe neonatal-onset encephalopathy with microcephaly yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
An X-linked recessive condition caused by mutation(s) in the MECP2 gene, encoding methyl-CpG-binding protein 2. It is characterized by severe neonatal encephalopathy.
Definition from the Mondo Disease Ontology (MONDO:0010397), read 2026-09-29. CC BY 4.0.
- Inheritance
- X-linked recessive inheritance
- Onset and course
- Congenital onset
HPO, annotations 2026-09-02
Features
19 features
What the disease is reported to present with, and how often among people who have it — never how often a feature means the disease. HPO, annotations 2026-09-02.
- EncephalopathyHPOHP:0001298
- 1 of 1 reported patient · Congenital onset
- Very frequent (80% to 99% of cases)
- ApneaHPOHP:0002104
- Very frequent (80% to 99% of cases)
- Respiratory insufficiencyHPOHP:0002093
- Very frequent (80% to 99% of cases)
- Severe global developmental delayHPOHP:0011344
- Very frequent (80% to 99% of cases)
- Bilateral tonic-clonic seizureHPOHP:0002069
- Frequent (30% to 79% of cases)
- EEG with focal slow activityHPOHP:0010843
- Frequent (30% to 79% of cases)
Show the remaining 7
- Poor suckHPOHP:0002033
- Frequent (30% to 79% of cases)
- SeizureHPOHP:0001250
- Frequent (30% to 79% of cases)
- SpasticityHPOHP:0001257
- Frequent (30% to 79% of cases)
- Cerebral atrophyHPOHP:0002059
- Occasional (5% to 29% of cases)
- High palateHPOHP:0000218
- Occasional (5% to 29% of cases)
- Multifocal epileptiform dischargesHPOHP:0010841
- Occasional (5% to 29% of cases)
Genes
1 gene
Germline variants in the gene encoding each protein, as classified by GenCC submitters, each in their own words. Limited, disputed and refuted submissions are listed too.
- MECP2HGNC:6990
- Definitive · G2P · X-linked · 2015
- Supportive · Orphanet · X-linked · 2021
Where it sits
Other names
3 names
Resolves to: severe neonatal-onset encephalopathy with microcephaly
- Also called
- encephalopathy, neonatal severe, X-linked recessivesevere congenital encephalopathy due to MECP2 mutationsevere neonatal encephalopathy due to MECP2 mutations