imperfecta

Osteogenesis imperfecta (OI) is a genetic disorder in which bones fracture (break) easily. Sometimes the fractures happen for no known reason. OI can also cause weak muscles, brittle teeth, a curved spine, and hearing loss. OI is caused by one of several genes that aren't working properly. When these genes don't work, it affects how you make collagen, a protein that helps make bones strong.

OI can range from mild to severe, and symptoms vary from person to person. A person may have just a few or as many as several hundred fractures in a lifetime.

There is no specific test for OI. Your doctor uses your medical and family history, physical exam, and imaging and lab tests to diagnose it. Your doctor may also test your collagen (from skin) or genes (from blood). There is no cure, but you can manage symptoms. Treatments include exercise, pain medicine, physical therapy, wheelchairs, braces, and surgery.

NIH: National Institute of Arthritis and Musculoskeletal and Skin Diseases

Your teeth are made of a hard, bonelike material. There are four parts:

• Enamel, your tooth's hard surface
• Dentin, the hard yellow part under the enamel
• Cementum, the hard tissue that covers the root and keeps your teeth in place
• Pulp, the soft connective tissue in the center of your tooth. It contains nerves and blood vessels.

You need your teeth for many activities that you may take for granted. These include eating, speaking and even smiling.

There are many different problems that can affect your teeth, including:

• Tooth decay - damage to a tooth's surface, which can lead to cavities
• Abscess - a pocket of pus, caused by a tooth infection
• Impacted tooth - a tooth that did not erupt (break through the gum) when it should have. It is usually wisdom teeth that are impacted, but it can sometimes happen to other teeth.
• Misaligned teeth (malocclusion)
• Tooth injuries such as broken or chipped teeth

The causes of tooth disorders varies, depending on the problem. Sometimes the cause is not taking good care of your teeth. In other cases, you may have been born with the problem or the cause is an accident.

The symptoms can vary, depending on the problem. Some of the more common symptoms include:

• Abnormal color or shape of the tooth
• Tooth pain
• Worn-down teeth

Your dentist will ask about your symptoms, look at your teeth, and probe them with dental instruments. In some cases, you may need dental x-rays.

The treatment will depend on the problem. Some common treatments are:

• Fillings for cavities
• Root canals for cavities or infections that affect the pulp (inside of the tooth)
• Extractions (pulling teeth) for teeth that are impacted and causing problems or are too damaged to be fixed. You may also have a tooth or teeth pulled because of overcrowding in your mouth.

The main thing that you can do to prevent tooth disorders is to take good care of your teeth:

• Brush your teeth twice a day with a fluoride toothpaste
• Clean between your teeth every day with floss or another type of between-the-teeth cleaner
• Limit sugary snacks and drinks
• Don't smoke or chew tobacco
• See your dentist or oral health professional regularly

Your bones help you move, give you shape and support your body. They are living tissues that rebuild constantly throughout your life. During childhood and your teens, your body adds new bone faster than it removes old bone. After about age 20, you can lose bone faster than you make bone. To have strong bones when you are young, and to prevent bone loss when you are older, you need to get enough calcium, vitamin D, and exercise. You should also avoid smoking and drinking too much alcohol.

Bone diseases can make bones easy to break. Different kinds of bone problems include:

• Low bone density and osteoporosis, which make your bones weak and more likely to break
• Osteogenesis imperfecta makes your bones brittle
• Paget's disease of bone makes them weak
• Bones can also develop cancer and infections
• Other bone diseases, which are caused by poor nutrition, genetics, or problems with the rate of bone growth or rebuilding

NIH: National Institute of Arthritis and Musculoskeletal and Skin Diseases

Your connective tissue supports many different parts of your body, such as your skin, eyes, and heart. It is like a "cellular glue" that gives your body parts their shape and helps keep them strong. It also helps some of your tissues do their work. It is made of many kinds of proteins. Cartilage and fat are types of connective tissue.

Over 200 disorders that impact connective tissue. There are different types:

• Genetic disorders, such as Ehlers-Danlos syndrome, Marfan syndrome, and osteogenesis imperfecta
• Autoimmune disorders, such as lupus and scleroderma
• Cancers, like some types of soft tissue sarcoma

Each disorder has its own symptoms and needs different treatment.

NIH: National Institute of Arthritis and Musculoskeletal and Skin Diseases

Genetic disorders are health conditions caused by changes (also called mutations or variants) in your genes. Genes are parts of DNA found in your cells that carry instructions for how your body grows, develops, and functions. Many genes tell your body how to make proteins, which are needed for your body to work properly.

A genetic disorder happens when a gene variant changes how a protein is made. The variant may cause the protein to work poorly or not be made at all. If genes don't make the right proteins, or don't make them correctly, it can lead to a genetic disorder.

Not all gene changes cause disease. Often, these changes have no effect. But sometimes, even a small change in DNA can affect how proteins are made.

Gene variants can be grouped into two main types:

• Inherited variants (also called germline variants) are passed down from your parents. They come from egg or sperm cells.
• Non-inherited (also called somatic variants) are not passed down from your parents. They happen during your lifetime. They may be caused by things like harmful chemicals or ultraviolet (UV) rays from the sun.

Genetic disorders may be caused by:

• Single gene disorders are caused by changes in one gene. Examples can include sickle cell anemia, where a change in a single gene can cause the condition, and Charcot-Marie-Tooth disease, where a variant in one of many different genes can cause the condition.
• Chromosomal disorders are caused by missing, extra, or altered chromosomes. Chromosomes are structures that carry genes. These disorders involve changes in the number of chromosomes people have or changes in the structure of one or more chromosomes. An example is Down syndrome, which is caused by an extra copy of chromosome 21.
• Complex (multifactorial) disorders are caused by changes in many genes. Each change alone may not cause the disease, but together they increase the risk. Lifestyle and environmental factors, such as exercise, diet, or exposure to pollutants, also play a role. Colon cancer is an example.

Some genetic conditions are passed down through families (inherited) in one of several patterns, depending on the specific gene involved.

Patterns of inheritance can include:

• Dominant means you only need one changed gene to cause the condition.
• Recessive means you need two changed copies of the gene (one from each parent) for the condition to occur.
• X-linked conditions involve genes located on the X chromosome. These conditions often affect males more frequently.
• Mitochondrial conditions are passed down by the mother.

Your health care provider may check for a genetic condition based on:

• A physical examination.
• Your personal medical history.
• Your family health history.
• Laboratory tests, including genetic testing.

NIH: National Library of Medicine