Diagnosis of XLH
Elizabeth and her mother, Jean, living with XLH
Do you suspect that you or your child might have X-linked hypophosphatemia (XLH)?
Early and accurate diagnosis of XLH is important so that the disease can be managed. Diagnosis of XLH is typically during childhood, usually within 1-2 years of age, when legs start supporting weight. During this time, you can also recognize common symptoms of XLH such as:
- Impaired growth and short stature
- Outward curving of the legs, also known as leg bowing, when a child is in a standing position
- Knock-knees, a condition when both the knees are at an angle touching each other
- Bone, muscle, and joint pain
- Dental abscesses, which appear as small, pus-filled ulcers in the gums
- Waddling gait while walking
- Enlargement of wrists and knees
- Misshapen head
The earlier XLH is identified, the better the chances are of managing the symptoms and, therefore, the disease.
XLH is not merely a pediatric disease. Since the disease progresses with time, adults continue to have it, too.
In some instances, adults with XLH may be misdiagnosed during childhood or can remain undiagnosed. They may continue to experience unresolved symptoms of their ongoing disease, such as:
- Bone pain
- Joint pain and stiffness
- Fractures and pseudofractures
- Early onset of osteoarthritis
- Dental abscesses
- Fatigue and weakness
“Three hundred times a day, I think about my joints hurting and how that’s going to affect my next few steps.”
—Melissa, XLH patient
If you suspect XLH in yourself or your child, seek the help of a doctor.
Diagnosing XLH can be tricky because it is a rare disease. It is important that you find doctors who are knowledgeable about XLH and can identify and manage the disease. These specialists are often found at university medical centers and specialize in metabolic bone disorders.
Endocrinologist (adult/pediatric)
Specializes in treating disorders that affect hormones
Nephrologist (adult/pediatric)
Specializes in treating diseases that affect the kidneys
Molecular geneticist
Specializes in treating genetic diseases
Find an XLH specialist near you
Play an active role during your visit.
It’s not easy to remember everything your healthcare provider will tell you during your visit. Keeping a diary to record symptoms, appointment dates, notes about medicines, and even jotting down questions you might have can help you keep track of the information you receive. The more engaged you are, the easier the diagnosis process and disease management will be for you and/or your child.
At your appointments, your doctor may:
Ask you questions about your family history of symptoms associated with XLH
Ask to complete laboratory tests requiring blood and urine samples to understand the levels of phosphate in the body and X-rays to evaluate the condition of the bones.
Use genetic testing to help confirm a diagnosis of hypophosphatemia
Following your initial diagnosis, your doctor may prescribe treatments that can help improve the symptoms of XLH
Help prevent misdiagnosis by engaging and voicing your concerns with your doctor.
Because XLH is a rare disease that affects anywhere from 1 in 20,000 to 1 in 25,000 people, it can be mistaken for other diseases, such as:
Nutritional rickets and other types of rickets disorders that can be inherited
Normal variations in the appearance of the legs (physiologic leg bowing)
Hypophosphatasia, a disease that also affects bones and teeth
Early and accurate diagnoses are key to improved symptom and disease management
