XLH is a genetic, lifelong, progressive condition
X-linked hypophosphatemia (or XLH) is a genetic, lifelong, progressive rare condition that affects up to 1 in 20,000 people.
stands for “X-linked,” which means the condition is passed down through the X chromosome.
stands for “hypophosphatemia,” which means that the levels of phosphorus in the blood are too low.
When the body loses too much phosphorus, it can affect the bones, muscles, and teeth of both children and adults.
why your body needs phosphorus
Strengthens bones and teeth
Helps muscle and nerve function
Helps produce and store energy levels
Supports growth
People with XLH have lower than normal levels of phosphorus in their blood.
Sunindiya
Living with XLH
Other names for XLH
Your doctor may refer to XLH by different names. You may have heard the term "rickets" before, which is used to describe soft or weak bones in children, commonly caused by a vitamin D deficiency.
XLH may also be called:
- Familial hypophosphatemia
- Familial hypophosphatemic rickets
- X-linked vitamin D–resistant rickets
- Vitamin D–resistant osteomalacia
- Genetic rickets
If you’ve heard any of these terms, they may be referring to XLH.
COMM-US-RDS-0998 August 2026