Just Received an XLH Diagnosis, Now What?

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by Mary Chapman |

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A diagnosis of X-linked hypophosphatemia (XLH) is the start of a lifelong journey. Here is some information about this disease and what you might expect.

About XLH

XLH is a rare genetic disease characterized by low phosphate levels in the blood. It can lead to a number of symptoms in children and adults, including bone abnormalities and muscle weakness and pain.

Your child may be prone to osteomalacia — soft and weak bones — early osteoarthritis, fractures, stunted growth, and dental abscesses.

Every patient experiences XLH differently. Symptoms vary widely in their nature and severity, and no two patients have the same signs or symptoms. Children may show some symptoms early in life, or none until they’re older.

What causes XLH?

Mutations in the PHEX gene cause XLH. This gene encodes for an enzyme that is predominantly active in the bones and teeth, and that regulates the synthesis of a phosphate-regulating protein called fibroblast growth factor 23 (FGF23) by mechanisms not well understood.

The mutations cause the circulating levels of FGF23 to be higher than normal, which decreases phosphate reabsorption in the kidneys. This results in low phosphate levels in the body.

Is the disease hereditary?

XLH is a hereditary condition, meaning most people inherit it from one of their parents. But it can also appear in a person spontaneously, which is reported to happen in 20-30% of cases.

When it’s hereditary, it is an X-linked dominant disorder, meaning that a single copy of a disease-causing mutation is sufficient to cause the disease.

Is it my fault?

Some parents may feel guilty or otherwise at fault when their child is diagnosed XLH. No one is to blame, however.

Although it’s initially challenging to move forward after a diagnosis, learning as much as you can about the condition can be a major help. So can going through counseling and getting in touch with a patient organization such as the XLH Alliance or the XLH Network. Such groups can also help to put you in touch with caregiver support organizations.

What can my child with XLH expect?

While doctors often diagnose XLH in people at young ages, it is a lifelong condition. However, with proper symptom management and support, its impact can be minimized, especially if it’s diagnosed early.

The standard treatment for children is a combination of phosphate salts taken orally three to five times a day, along with an appropriate dose of calcitriol, the active form of vitamin D.

Your child may experience difficulties in carrying out everyday activities, including going to school. They may need an individualized education plan, and accommodations such as ramps, lifts, specialized equipment, or help with writing notes.

As the disease progresses, patients can have difficulty walking and completing daily tasks. Aids and adaptations can help, as can procedures that may become necessary, including orthopedic or craniofacial surgeries.

Are new therapies on the way?

The last two decades have brought more knowledge about our genetic makeup than ever before. As a result, we understand more about genetic conditions such as XLH. This knowledge is helping researchers working to develop or improve XLH treatments.


Last updated: Oct. 30, 2020


XLH News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health providers with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.