COL2A1 and Stickler syndrome: In contrast, characteristics of the Marshall-Stickler syndrome spectrum caused by COL11A1 differ from those caused by COL2A1, with patients harboring COL11A1 variants exhibiting more severe hearing impairment but rare vitreoretinal degeneration and retinal detachments compared to those with COL2A1 variants (Annunen et al., 1999).