C syndrome
Findings
No curated finding names C syndrome yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
C syndrome is a rare multiple congenital anomaly/intellectual disability syndrome characterized by trigonocephaly and metopic suture synostosis, dysmorphic facial features, short neck, skeletal anomalies, and variable intellectual disability.
Definition from the Mondo Disease Ontology (MONDO:0008893), read 2026-09-29. CC BY 4.0.
- Onset and course
- Death in infancy
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.
- Anteverted naresHPOHP:0000463
- Very frequent (80% to 99% of cases)
- Biparietal narrowingHPOHP:0004422
- Very frequent (80% to 99% of cases)
- Clinodactyly of the 5th fingerHPOHP:0004209
- Very frequent (80% to 99% of cases)
- CryptorchidismHPOHP:0000028
- Very frequent (80% to 99% of cases)
- Depressed nasal bridgeHPOHP:0005280
- Very frequent (80% to 99% of cases)
- EpicanthusHPOHP:0000286
- Very frequent (80% to 99% of cases)
Show the remaining 41
- MicrocephalyHPOHP:0000252
- Very frequent (80% to 99% of cases)
- MicrognathiaHPOHP:0000347
- Very frequent (80% to 99% of cases)
- Posteriorly rotated earsHPOHP:0000358
- Very frequent (80% to 99% of cases)
- Short neckHPOHP:0000470
- Very frequent (80% to 99% of cases)
- Short noseHPOHP:0003196
- Very frequent (80% to 99% of cases)
- Smooth philtrumHPOHP:0000319
- 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.
- CD96HGNC:16892
- Limited · Ambry Genetics · Autosomal recessive · 2018
- Limited · ClinGen · Autosomal dominant · 2025
- Limited · Labcorp Genetics (formerly Invitae) · Unknown · 2020
- Limited · G2P · Autosomal dominant · 2021
Where it sits
Other names
5 names
Resolves to: C syndrome
- Also called
- Opitz C trigonocephalyOpitz trigonocephaly C syndromeOpitz trigonocephaly syndromeOTCStrigonocephaly C syndrome