Conditions We Treat

The OI team at Phoenix Children’s diagnoses and treats a wide range of common and more complex conditions affecting children and teens. These include:

• Fibrous dysplasia – A rare bone disorder that causes certain bones to be replaced by abnormal scar-like (fibrous) connective tissue. This often leads to pain and weakened bones prone to fracture.
• Hypophosphatasia – A rare genetic condition that causes impaired mineralization of the bones and teeth. This condition leads to bones that are soft and prone to deformity and fracture.
• Hypophosphatemic rickets (XLH) – A rare genetic condition that causes low phosphate levels in the blood from phosphorus losses in the urine. This often causes soft and weak bones, as well as other features including bowed legs, bone pain, short stature and dental issues.
• McCune-Albright syndrome – An extremely rare disorder that affects the bones, skin and hormone-producing glands. In this syndrome, some bones may be replaced by scar-like tissue (polyostotic fibrous dysplasia) causing bone pain and fragility. The skin may have characteristic brown patches (café au lait spots). There also may be dysfunction of certain growth-regulating glands causing increased hormone production.
• Osteogenesis imperfecta (OI) – Also known as brittle bone disease. OI may cause soft bones that break (fracture) easily, bones that are not formed normally and other problems. There are more than 20 known genetic causes of OI, and symptoms range from mild to severe.
  • OI type I: As the mildest and most common form, OI type I causes muscle weakness and few broken bones. About 50% of people affected by OI have type I.
  • OI type III: Babies with OI type III typically have broken bones at birth and severe physical disabilities. 
  • OI type IV: With bone deformities and symptoms that can range from mild to severe, children with OI type IV experience most bone breaks before puberty.
• Osteopetrosis – Also known as marble bone disease, osteopetrosis is a genetic disorder that causes bones throughout the body to grow abnormally and become overly dense due to a defect in bone reabsorption. This disease may cause brittle bones that fracture easily, low blood cell production and low blood calcium levels, as well as liver and spleen enlargement. Symptoms may include enlarged head circumference, excessive fluid on the brain and loss of cranial nerve function (blindness, deafness and facial nerve paralysis), as well as dental and jaw problems.
• Stickler syndrome – A group of connective tissue disorders that can affect the eyes, ears, skeleton and joints. This syndrome can be characterized by eye abnormalities, cataracts, retinal detachments, sensorineural hearing loss, flat mid-face, small nose and chin, palate abnormalities, joint hypermobility, spine curvature or early osteoarthritis.