syndromic X-linked intellectual disability 34
Findings
No curated finding names syndromic X-linked intellectual disability 34 yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
Macrocephaly-intellectual disability-left ventricular non compaction syndrome is a rare, genetic, syndromic intellectual disability characterized by motor and cognitive developmental delay with language impairment, macrocephaly, hypotonia, dysmorphic facial features (including long face, slanting palpebral fissures and prominent, flattened nose) and left ventricular noncompaction cardiomyopathy. Patients also present skeletal abnormalities (e.g. scoliosis, finger clinodactyly, pes planus), slender build and shy behavior. Strabismus and various neurological signs (including ataxia, tremor and hyperreflexia) may be associated, as well as epilepsy, autism and MRI findings showing a small cerebellum and abnormalities of the corpus callosum. A phenotypic variant with no cardiac involvement has been reported.
Definition from the Mondo Disease Ontology (MONDO:0010501), read 2026-09-29. CC BY 4.0.
- Inheritance
- X-linked recessive inheritance
HPO, annotations 2026-09-02
Features
103 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.
- AtaxiaHPOHP:0001251
- 1 of 1 reported patient
- Occasional (5% to 29% of cases)
- Atrial septal defectHPOHP:0001631
- 2 of 2 reported patients
- Occasional (5% to 29% of cases)
- AutismHPOHP:0000717
- 1 of 1 reported patient
- Occasional (5% to 29% of cases)
- Axial hypotoniaHPOHP:0008936
- 1 of 1 reported patient
- CardiomegalyHPOHP:0001640
- 1 of 1 reported patient
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.
- NONOHGNC:7871
- Strong · Labcorp Genetics (formerly Invitae) · X-linked · 2023
- Strong · G2P · X-linked · 2016
- Strong · PanelApp Australia · X-linked · 2025
- Supportive · Orphanet · X-linked · 2021
Where it sits
Other names
12 names
Resolves to: syndromic X-linked intellectual disability 34
- Also called
- intellectual developmental disorder, X-linked syndromic 34intellectual disability, X-linked, syndromic 34intellectual disability, X-linked, syndromic type 34macrocephaly-intellectual disability-left ventricular non compaction syndromemental retardation, X-linked, syndromic 34mental retardation, X-linked, syndromic type 34MRXS34MRXSMLNONO X-linked syndromic intellectual disabilitysyndromic X-linked intellectual disability Mircsof-Langouet typesyndromic X-linked intellectual disability type 34X-linked syndromic intellectual disability caused by mutation in NONO