What Is Collagen? Collagen (KOL-uh-jin) is a protein in the body. Different types of collagen are in many body parts, including hair, skin, nails, bones, ligaments, tendons, cartilage, blood vessels, and intestines. What Does Collagen Do? Collagen has many different roles in the body. It: helps make bones strong lets the skin and tendons stretch helps with healing after an injury What Are the Different Kinds of Collagen? Our bodies have many different kinds of collagen. Most of it is type I collagen, found in bones and tendons. But we also have: type II collagen, found in cartilage (the bendable material in the nose, ears, and joints) type III collagen, found in skin, the lining of blood vessels, and the intestines What Problems Can Happen With Collagen? Depending on which type of collagen is affected, problems can include: osteogenesis imperfecta (also called brittle bone disease), caused by a problem with type I collagen Elhers-Danlos syndrome (which leads to stretchy skin and joints), often caused by a problem with type IV collagen The symptoms of problems with collagen can vary greatly. Some people have very mild symptoms, while others have moderate or more severe symptoms. How Do Problems With Collagen Happen? Most kids with a collagen problem have it because they inherited a gene from one or both of their parents. But sometimes it happens in a child without a family history. What Else Should I Know? Collagen has many important roles in the body. A child who has a collagen problem may need medical care throughout life. To help your child get the best care possible: Find out all you can about your child's medical condition. If your child is old enough, talk about the problem. Use simple words and let your child ask questions. Be positive, but honest. Take your child to all medical appointments. Follows the health care provider's treatment recommendations. Back to Articles Related Articles 3 Ways to Build Strong Bones We build almost all our bone density when we're kids and teens. Kids with strong bones have a better chance of avoiding bone weakness later in life. Here's how parents can help. Read More Bones, Muscles, and Joints Our bones, muscles, and joints form our musculoskeletal system and enable us to do everyday physical activities. Read More Bones, Muscles, and Joints Without bones, muscles, and joints, we couldn't stand, walk, run, or even sit. The musculoskeletal system supports our bodies, protects our organs from injury, and enables movement. Read More Broken Bones Bones are tough stuff - but even tough stuff can break. Find out what happens when a bone fractures. Read More Broken Bones Many kids will have a broken bone at some point. Here's what to expect. Read More Broken Bones What happens when you break a bone? Read More Your Bones Where would you be without your bones? Learn more about the skeletal system in this article for kids. Read More How Broken Bones Heal Broken bones have an amazing ability to heal, especially in kids. Full healing can take time, but new bone usually forms a few weeks after an injury. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.