Christianson syndrome
Findings
No curated finding names Christianson syndrome yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
A very rare form of syndromic intellectual deficit characterized by microcephaly, severe developmental delay or regression, hypotonia, abnormal movements, and early-onset seizures.
Definition from the Mondo Disease Ontology (MONDO:0010278), read 2026-09-29. CC BY 4.0.
- Inheritance
- X-linked recessive inheritance
HPO, annotations 2026-09-02
Features
53 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.
- Absent speechHPOHP:0001344
- 11 of 11 reported patients · Male
- Very frequent (80% to 99% of cases)
- AtaxiaHPOHP:0001251
- 11 of 11 reported patients
- Interictal epileptiform activityHPOHP:0011182
- 11 of 11 reported patients
- Profound global developmental delayHPOHP:0012736
- 11 of 11 reported patients
- SeizureHPOHP:0001250
- 11 of 11 reported patients
- Frequent (30% to 79% of cases)
- StrabismusHPOHP:0000486
- 11 of 11 reported patients
- Very frequent (80% to 99% of cases)
Show the remaining 41
- Long faceHPOHP:0000276
- Very frequent (80% to 99% of cases)
- MacrotiaHPOHP:0000400
- Very frequent (80% to 99% of cases)
- Narrow faceHPOHP:0000275
- Very frequent (80% to 99% of cases)
- Neuronal loss in central nervous systemHPOHP:0002529
- Very frequent (80% to 99% of cases)
- Profound intellectual disabilityHPOHP:0002187
- Very frequent (80% to 99% of cases)
- Severe global developmental delayHPOHP:0011344
- Very frequent (80% to 99% 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.
- SLC9A6HGNC:11079
- Definitive · ClinGen · X-linked · 2018
- Definitive · G2P · X-linked · 2015
- Strong · PanelApp Australia · X-linked · 2025
- Supportive · Orphanet · X-linked · 2021
Where it sits
- A kind of
Other names
6 names
Resolves to: Christianson syndrome
- Also called
- intellectual developmental disorder, X-linked syndromic, Christianson typeintellectual disability, microcephaly, epilepsy, and ataxia syndromeintellectual disability, X-linked syndromic, Christianson typemental retardation, microcephaly, epilepsy, and ataxia syndromeMRXSCHX-linked Angelman-like syndrome