About X-linked Hypophosphatemia

X-linked hypophosphatemia related PHEX gene is located on the X chromosome.
X-linked Hypophosphatemia (XLH) is a rare genetic disorder characterized by low levels of phosphate in the blood, caused by mutations in the PHEX gene on the X- chromosome.

Prevalance / Onset

Map background with the silhouette of a baby and words saying "X-linked hypophosphatemia affects 1 in 20,000 to 60,000 new births globally."


XLH affects between 1 in 20,000 and 1 in 60,000 new births.


As the child starts to bear weight on their legs, symptoms become apparent. This can occur between the ages of 8 and 16 months after birth.


Nine symptoms: Bone pain, Muscle pain and weakness, A waddling gait, Joint pain caused by the hardening of tendons and ligaments, Abnormal tooth development, Tooth abscesses, Dental pain, Rickets(for children), Osteomalacia(for adults)

Inheritance Pattern

Three family trees showing each possible case of x-linked hypophosphatemia affecting mother only, father only, and both.
The XLH inherits in the X-linked dominant pattern. Males and females are affected similarly.


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  2. Even though patients with XLH mainly shows rickets (or osteomalacia), it cannot be treated with vitamin D like usual rickets.

Burosumab (Crysvita® FDA approved) Burosumab is used to normalize phosphate levels.

For children
Phosphate supplements are generally required with high dose calcitriol. Growth hormones are used to improve growth in children.

For adults
Reducing pain is the main goal for adult patients. Corrective surgery to fix bowed or bent legs can be necessary.

Living with X-linked Hypophosphatemia

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  2. Physical Therapy
    Physical therapy may help relieve pain and stiffness by improving the stability and flexibility of joints and muscles.

Occupational Therapy
Occupational therapy may improve the ability to manage daily activities.

Stay Active
Exercises, such as yoga, may benefit patients. Consult with your doctor to make sure certain exercises are right for you.

Helpful communities for X-linked Hypophosphatemia

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