X-Linked Hypophosphatemia (XLH) is caused by one of several mutations of the PHEX gene, all of which cause XLH. There does not seem to be any correlation between the specific mutation and the severity of the symptoms experienced. Those with XLH generally exhibit the following:
Abnormal bone and tooth development, which may range from mild or moderate to severe.
Rickets that resists traditional Vitamin D therapy.
A few people with XLH exhibit no bone-related symptoms, and a study published in 1994 notes that it’s not uncommon for XLH to go undiagnosed in those with mild to moderate symptoms.
Lower limb deformities (bow or knock-knee)
Waddling gait
Short stature or declining growth rate
Spontaneous tooth abscesses
Bone pain
Muscle pain and weakness
