]> 2026-07-31T16:30:54+00:00 WBR0603 0 en Hyaline cartilage Hyaline cartilage contains type II collagen Smooth muscle Smooth muscles contain type III collagen Dermis Dermis (skin) contains type I collagen Kidney Kidney contains type III collagen Basement membrane Basement membrane contains type IV collagen The girl in this vignette has a condition known as Osteogenesis Imperfecta (OI). Osteogenesis imperfect (also known as brittle bone disease or "Lobstein syndrome") is an autosomal dominant bone disorder characterized by bones that are prone to fracture. People with OI are born with defective connective tissue, or without the ability to make it, usually because of a mutation in the genes coding for type-I pro-collagen i.e. COL1A1 and COL1A2. There are seven subtypes varying in severity, age of presentation, and clinical features. Classic signs and symptoms include: fractures after minor trauma, blue tint of the white part of the eye and deafness. Type I collagen is found in bone, skin (dermis), tendon, dentin, fascia, cornea, late wound repair/mature scar, fibrous cartilage Type II – Hyaline and elastic cartilage, vitreous body, nucleus pulposus Type III – Skin, blood vessels, uterus, smooth muscle, liver, kidney, lung, spleen, fetal tissue, granulation tissue/early wound repair Type IV – Basement membrane<br/> '''Educational Objective:''' Defective type I collagen found in Osteogenesis Imperfecta is responsible for the brittle bones, lax ligaments and tendons. The characteristic blue-gray sclera is pathognomonic.<br/> '''References:''' Forlino, Antonella, et al. "New perspectives on osteogenesis imperfecta." Nature Reviews Endocrinology 7.9 (2011): 540-557.<br> First Aid 2015 page 76 Genetics Pathology C Musculoskeletal/Rheumatology 2020-10-28T01:09:07Z 2459150.5479977 WBR0603