Variable phenotypic expression of Stickler syndrome occurs both within families and between families.
Interfamilial variability is in part explained by locus and allelic heterogeneity.
The diagnosis of Stickler syndrome is clinically based. At present, no consensus minimal clinical diagnostic criteria exist. Hypermobility, mild spondyloepiphyseal dysplasia, precocious osteoarthritis. COL11A1 may be tested first in patients with typical ocular findings and significant hearing loss. Other phenotypes associated with mutations in COL11A1 .