However, EDSs are also linked to abnormalities in proteoglycans, notably in the progeroid and musculocontractural types of EDS, as well as alterations in an endoplasmic reticulum folding protein (observed in EDS with progressive kyphoscoliosis, myopathy, and hearing loss), transcription factors (associated with Brittle cornea types 1 and 2), and a zinc transporter [19,39,67]. Here, PROS1 is linked to Ehlers-Danlos syndrome.