What is XLH?

X-linked hypophosphatemia (XLH) is a genetic disease that affects the health of bones in both children and adults.

Cera, living with XLH

Phosphorus

Children with XLH don’t have enough phosphorus in their bodies. Phosphorus is a mineral that is important to the health and function of bones, muscles, and teeth. Having too little phosphorus—a condition called hypophosphatemia—can cause bones to become weak, leading to childhood conditions like rickets.

Rickets

Rickets is a major symptom of XLH, and it usually becomes apparent once a child begins standing or walking (about 1 to 2 years of age). Rickets can cause pain, delayed growth, and bone abnormalities in the legs. As a result, children with XLH may face physical challenges.

Impaired growth

Low levels of phosphorus can affect bone growth, so children with XLH tend to be short for their age. In children with XLH, the bones tend to bend inward or outward and leads to shorter height.

Image of doctor discussing XLH treatment options

When discussing XLH treatment options with your child’s doctor:

Ask about the impact of having low phosphorus levels, including the long-term effects of rickets and delayed growth and how that may affect your child.

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Phosphorus

Adults with XLH continue to have low levels of phosphorus in their bodies. Phosphorus is a mineral that is just as important for the health and function of bones, muscles, and teeth in adults as it is in children. Not having enough phosphorus can cause osteomalacia, a condition often described as the weakening of bones. Osteomalacia continues throughout adulthood.

$Osteomalacia and fractures icon$

Osteomalacia and fractures

Osteomalacia weakens bones, making them prone to break easily. People who have XLH don’t have enough phosphorus in their bodies for bones to properly mineralize, which causes some parts of bones to be more likely to fracture, or break. Bones in the feet, legs, and hips are vulnerable to fractures and pseudofractures, which can be painful and limit a person’s ability to move.

Joint stiffness

Adults with XLH commonly experience physical symptoms resulting from osteomalacia and deformed bones and joints. These can include joint pain and stiffness, which may restrict range of motion.

Doctor discussing XLH treatment options with adult patient

When discussing XLH treatment options with your doctor:

Be open about all symptoms you are currently experiencing
Ask for a skeletal evaluation to check for possible fractures
Remember that phosphorus is important for healthy bones even when you’re an adult

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What is XLH?

XLH in children

TREATMENT GOALS IN CHILDREN WITH XLH MAY INCLUDE:

When discussing XLH treatment options with your child’s doctor:

XLH in Adults

Treatment goals in adults with XLH may include:

When discussing XLH treatment options with your doctor:

What is CRYSVITA?

Important Safety Information

What is CRYSVITA?

Important Safety Information