X-Linked Hypophosphatemia (XLH) Clinical Trials

X-Linked Hypophosphatemia occurs when the body produces too much of a hormone called FGF23, which causes the kidneys to waste phosphate. This disrupts bone mineralization and leads to rickets in children and ongoing bone and joint problems in adults. The condition affects both skeletal development and dental health, with children commonly experiencing delayed growth, bone deformities, and dental complications.

The most common symptoms of X-Linked Hypophosphatemia include Bowed legs or knee deformities, Short stature or slowed growth, Bone and muscle pain or weakness, Delayed walking or mobility problems in children, Dental problems including recurrent tooth abscesses, among others. Approximately 1 in 20,000 people. Symptoms can range from mild to severe and may vary between individuals.

Trial Friend lists all active clinical trials for X-Linked Hypophosphatemia from ClinicalTrials.gov, with eligibility criteria translated into plain English. Patients can filter by trial phase and recruitment status, search by location, and use the Match Me tool to score trials against their profile. Burosumab (Crysvita) is the only FDA-approved targeted treatment for XLH and works by blocking FGF23, the hormone causing phosphate loss. It is approved for children as young as 6 months and for adults.

As of September 2026, Trial Friend's curated drug index does not include an FDA-approved treatment specific to X-Linked Hypophosphatemia. The Treatments section of this page checks FDA drug labels live and lists any approved drug whose label names the condition, and the trials listed below cover the investigational options.

X-Linked Hypophosphatemia is caused by variants in the PHEX gene. Females with one PHEX variant are affected much like males; fathers pass it to all daughters and no sons.

It is X-linked dominant, so it affects girls as well as boys, and an affected parent has a 1 in 2 chance of passing it to each child. Approximately 1 in 20,000 people. Genetic testing confirms the diagnosis.

Yes. Genetic testing for X-Linked Hypophosphatemia looks at the PHEX gene. Females with one PHEX variant are affected much like males; fathers pass it to all daughters and no sons.

It is X-linked dominant, so it affects girls as well as boys, and an affected parent has a 1 in 2 chance of passing it to each child.

A confirmed variant establishes the diagnosis and is often required to enroll in gene-specific trials. The labs currently offering the test are listed in the Genetic Testing section of this page, pulled live from the NIH Genetic Testing Registry. A genetic counselor can help interpret the result and decide which relatives should be tested.

Eligibility for X-Linked Hypophosphatemia clinical trials depends on factors like age, diagnosis, treatment history, and overall health. Each trial sets its own inclusion and exclusion criteria. Trial Friend translates these requirements from medical language into plain English so patients can review them more easily. The Match Me tool can score your profile against active trials to help identify studies that may be a fit.

Participating in a X-Linked Hypophosphatemia clinical trial typically involves scheduled visits, medical tests, and close monitoring by a research team. Depending on the study phase, you may receive an investigational treatment, a placebo, or the current standard of care. Trials may last from a few weeks to several years. Study participation is voluntary, and you can withdraw at any time.