This is a genetic disorder that negatively affects the bones and teeth. It may also cause muscle weakness, deafness, and other health problems. It is called X-linked hypophosphatemia (XLH), and it happens due to a genetic change (mutation). This mutation causes the body to lose too much bone-strengthening phosphate. Physicians usually treat this condition with Burosumab, monoclonal antibody treatments, and physical therapy.
Children with XLH usually experience walking problems and may also have bowed legs.
Symptoms
Commonly, the first symptoms of this disease appear during early childhood. Check some examples below:
- Short stature
- Muscle and bone pain
- Walking problems
- Muscle weakness
- Reduced energy levels
- Physical differences in the head and shape of the face (often caused by craniosynostosis)
- Bowing legs or knees (also known as knock knees)
- Dental problems (including very early loss of baby teeth, tooth pain, abscesses, or frequent cavities)
Additional symptoms may occur in older people with XLH. For example:
- Deafness (hearing loss)
- Headaches
- Joint stiffness
- Fatigue (extreme tiredness)
- An increased risk of bone fractures
- Hardening of the tendons and ligaments
- Loss of adult teeth
- Problems with balance or walking
- Osteomalacia
- Spinal stenosis
If you or your child experiences any of the previous symptoms or others that cause concerns, immediately contact your healthcare provider.
Causes
This genetic disorder occurs due to a mutation (change) in the PHEX gene. This gene is responsible for the production of FGF23 (fibroblast growth factor 23). It is a hormone that helps regulate the amount of phosphate. These phosphates are very important in maintaining healthy bones. Reduced levels of phosphates in the blood may cause bone weakness, which significantly increases the risk of osteoporosis and bone fractures. In people with XLH, the abnormal gene causes the kidneys to remove more phosphates than needed.
Is X-linked Hypophosphatemia Inherited?
This condition is an X-linked autosomal dominant pattern, which means anyone who gets this abnormal gene develops XLH. Normally, women have 2 X chromosomes while men have one X and one Y. Generally, there is a 50% chance of passing the abnormal gene to the biological children. However, males can pass the gene to female children only, but not to male ones.
Furthermore, there are some diagnosed XLH without a family history of the disease. In such cases, the genetic mutation develops randomly during pregnancy.
Risk Factors
Physicians have identified some factors that may increase your risk of developing XLH. For example:
- Frequent diuretic use
- Alcohol use disorder
- Burns
- Starvation
- A family history of XLH
- Rarely, a person may develop a new mutation randomly, even without a family history of the disease
What Are The Possible Complications of XLH?
People who develop this genetic condition may also experience a variety of complications, especially if they ignore the symptoms and do not get treatment. Check some of them below:
- Deformities
- Osteoarthritis
- Periodontal disease
- Deafness
- Spinal stenosis
- Enthesopathy
- Encephalopathy
- Seizures
- Chronic kidney disease
- Nephrocalcinosis
- Hypertension (high blood pressure)
- Hyperparathyroidism (overactive parathyroid glands)
This article does not contain a full list of XLH complications. For more details, discuss it with your doctor. Moreover, you can talk with your doctor about ways to reduce the risk or prevent previous complications.
How to Prevent XLH?
This condition cannot be prevented because physicians do not fully understand why it happens. However, you can perform some genetic tests to make sure you do not have this abnormal gene before becoming pregnant.
Diagnosis
Doctors may perform a physical examination to check for abnormalities linked to the disease and ask some questions about the symptoms and family history. Usually, to confirm the condition and exclude others that cause symptoms similar to XLH, they will perform some tests. These include:
- Bone density tests
- Imaging tests (such as X-rays)
- Genetic tests
- Blood or urine tests check Phosphate and FGF23 levels
Treatment
While there is no cure for this condition, doctors prescribe treatments to lessen the symptoms and prevent serious complications. Check below some treatments often recommended for people with XLH:
- Physical therapy
- Surgery
- Monoclonal antibody treatments (such as Burosumab)
- Phosphate supplements and vitamin D (calcitriol)
- Occupational therapy
- Growth hormones (they help treat short stature)
- Hearing aids
Sometimes, physicians may recommend specific surgeries or procedures to treat broken bones or severe dental problems.
Frequently Asked Questions
What can I expect if I have XLH?
It is very important to monitor the condition regularly and get treatment as soon as possible for XLH complications. Otherwise, it may lead to permanent damage and other serious health problems.
What is the life expectancy for someone with XLH?
According to some recent studies, people with XLH have a shorter life expectancy, with about 8 years compared to a person without this genetic disorder. However, more research is needed to confirm these studies.
When should I go to the ER?
It is recommended to go to a dentist immediately if you experience any of the following symptoms. Examples include:
- Severe toothache
- Badly cracked or broken tooth
- Extruded tooth
- Dental abscess (when it occurs, you may experience swelling of the face and jaw)
Is XLH a disability?
This condition can be considered a disability because it causes limited movements and walking problems that may interfere with daily activities. Moreover, some people may also experience extreme tiredness, hearing loss, and other symptoms. Ask your healthcare professional if you have additional questions.
