- Treatment goals include optimizing growth and functionality, increasing phosphate levels in the body, and managing pain.
- Treatments are ongoing, and include newer targeted therapies available for children and adults.
- A combination of treatments may be necessary to address related issues.
X-linked hypophosphatemia (XLH) is a progressive, inherited condition where phosphate levels in the blood are abnormally low. The low levels can affect the development of strong bones and teeth and also result in damage to both over time.
Currently, there’s no cure for XLH. Treatment tends to focus on preventing future problems, reducing the severity of existing symptoms, and improving your quality of life.
- muscle contraction
- nerve functioning
- bone and teeth formation and growth
The reduction of phosphate in the bones leads to a form of phosphate deficient rickets. According to the Hormone Health Network, some of the first signs of XLH include undiagnosed fractures, tenderness of major joints, and pain in bones.
What is the goal of treatment?
According to the Genetic and Rare Diseases Information Center, the primary goals of XLH treatment vary based on your age.
For children, the primary goal is to provide enough calcium and phosphate for them to grow.
For adults, the main treatment goal for XLH includes managing pain.
As the Hormone Health Network notes, the main goal of treatment overall is to increase the amount of phosphate in your body so that growth and functionality are minimally impaired.
Treatments for XLH typically involve managing the condition and preventing it from getting worse. Though new treatment options may become available, some current options include the following.
Phosphate and active vitamin D
According to a treatment review, treatment options are relatively limited. The conventional treatment includes taking phosphate and active calcium supplements. Following this approach, you’d need to take between four and six doses each day.
| Medication | Dose | Frequency |
| Phosphate salts | ||
| Active vitamin D | adjusted for phosphate dose | 2 to 6 doses per day |
Dosing varies based on a person’s age as well as weight. Research has indicated that the best approach is to have the lowest effective dose of phosphate with higher doses of active vitamin D.
Burosumab (Crysvita)
In 2018, the Food and Drug Administration (FDA) approved the use of burosumab for the treatment of XLH. Burosumab is a targeted therapy that helps your body retain phosphorus.
The medication is delivered through injections administered by a member of your healthcare team. It’s a treatment option for both children and adults with XLH.
| Medication | Strengths | Frequency |
| Crysvita (burosumab) | 10 mg/mL, 20 mg/mL, or 30 mg/mL injections | once every 2 to 4 weeks |
When taking burosumab, your doctor will need to monitor serum phosphorus levels regularly. When levels are low, the next dose may be increased. If they’re high, the doctor may decrease the dose.
Surgery
In some cases, your doctor may recommend surgery. A doctor may recommend surgery to correct bowed or bent legs.
Oral care
If you’re living with XLH, you should maintain your oral health. This includes self-care, such as brushing teeth and flossing, and regular visits to the dentist.
Good oral hygiene and vigilance may help prevent issues in the mouth such as tooth abscesses and other issues.
Other therapies
Your treatment may involve a multidisciplinary approach. Research has indicated that you may need therapies that include:
- pharmacological treatment
- treatment for hearing loss
- orthopedic interventions
- physical therapy
- prevention of primary or secondary complications
- dental care
- genetic counseling
As a result, your treatment team may need to consist of members like:
- nephrologists
- orthopedic surgeons
- neurosurgeons
- rehabilitation physicians
- physical therapists
- dentists
- psychologists
- primary care doctors
- neurologists
- endocrinologists
- orthodontists
- ophthalmologists
- social workers
Treatment for XLH can put you at risk for some side effects.
According to the National Organization for Rare Disorders, side effects of phosphate salts and vitamin D treatment can include:
- excess levels of calcium in the urine (hypercalciuria)
- excess levels of calcium in the blood (hypercalcemia)
- calcium deposits in the kidneys (nephrocalcinosis)
Due to these concerns, your doctor will need to monitor your phosphate levels regularly and adjust medication levels accordingly.
If your doctor prescribes burosumab, you may experience side effects such as:
- constipation
- fever
- diarrhea
- cough
- injection site reaction
- rash
- vomiting
- pain in extremities
- nausea
- headache
- tooth abscess
- dental caries
- vitamin D decreased
If you’re living with and treating XLH, you’ll need regular appointments with doctors and other healthcare team members. During treatment, you’ll need regular blood work to monitor the effectiveness of treatment. Regular checks can help your doctor adjust your medication dosage.
If you feel like your doctor isn’t listening to your concerns, you’re not alone.
You should work with your treatment team to create the best treatment plan for your needs. This should include managing symptoms and any other issues associated with XLH, such as addressing mental health concerns.
While there’s no cure for XLH, early and regular treatment can help prevent disease progression, reduce symptoms, and improve overall quality of life.
Treatment often consists of taking phosphate and vitamin D supplements frequently throughout the day. The newest treatment, burosumab, provides targeted treatment for both adults and children.
Other therapies, such as dental care, surgery, and therapy may be done as needed to help improve symptoms and quality of life.