What is XLH?
X-Linked Hypophosphataemia (XLH) is a rare genetic disorder that affects about one in 20,000 people. The key characteristic of XLH is a low level of phosphorus in the blood, called Hypophosphataemia. When a person is affected by XLH, their kidneys do not properly handle Vitamin D and phosphorus. This causes a variety of symptoms and disorders that affect their bones and teeth.