Overview
Knobloch syndrome is a rare autosomal recessive disorder caused by mutations in COL18A1 (encoding collagen XVIII/endostatin), characterized by high myopia, vitreoretinal degeneration, retinal detachment, and occipital encephalocele. The retinal phenotype is severe, with early-onset retinal detachment and progressive visual loss. The occipital encephalocele may be subtle or absent in some patients, making the diagnosis challenging.
Genetics
Caused by COL18A1 mutations affecting collagen XVIII, a component of basement membranes and precursor to endostatin. Autosomal recessive.
| Gene | Locus | Inheritance | Notes |
|---|---|---|---|
| COL18A1 | 21q22.3 | AR | Collagen type XVIII alpha-1; endostatin precursor; sole known cause |
Clinical Presentation
Neonatal/Infancy
- Occipital encephalocele (variable)
- High myopia
- Lens dislocation in some
Childhood
- Vitreoretinal degeneration
- Retinal detachment
- Progressive visual loss
Diagnosis
- Neuroimaging: Occipital encephalocele or scalp defect
- Ocular examination: High myopia, vitreous degeneration
- Genetic testing: COL18A1 sequencing
Current Research & Treatment
No specific treatments available. Surgical repair of retinal detachment and encephalocele. Genetic counseling for families.
Active Clinical Trials
The following active clinical trials are investigating treatments for Knobloch Syndrome. Trial status and enrollment may change; always verify directly on ClinicalTrials.gov.