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). The gene discussed is COL11A1; the disease is hearing loss disorder.