“It’s just this lovely surprise of being able to make it to ladies’ night or to walk my dog.”
—Aly, age 41
Connect with a community of support for X-linked hypophosphatemia (XLH)
A method of assessing bone quality from bone biopsy samples. Histomorphometry includes assessments of osteoid volume to bone volume, osteoid thickness, and mineralization lag times.
A treatment that consists of oral phosphate and active vitamin D analogs (e.g., calcitriol, paricalcitol,
doxercalciferol, calcifediol) and was the active control in the Phase 3 study in pediatric patients with XLH.
A protein that plays a role in phosphate homeostasis. In XLH, the excess circulating FGF23 leads to increased
signaling, resulting in impaired phosphate uptake.
A statistic for the estimate of the mean after adjusting for the effect of other variables in a study.
The interval between osteoid formation and osteoid mineralization. In XLH, mineralization lag times are long, pointing to abnormalities in the process of bone mineralization.
An unmineralized organic tissue that eventually undergoes calcification and is deposited as lamellae or layers in the bone matrix.
A measurement of the amount of unmineralized bone.
A ratio of unmineralized bone to mineralized bone. In XLH, this ratio is large, pointing to a greater presence of
A softening and weakening of the bones that can occur throughout adulthood, caused by deficiencies in vitamin D, calcium, or phosphate, resulting in abnormal osteoid mineralization. In children, osteomalacia can occur simultaneously with rickets.
Phosphate-regulating endopeptidase homolog X-linked. Variants in this gene cause X-linked hypophosphatemic rickets.
In study 4, physical function was described as activities associated with independent movement—such as walking, standing, getting into or out of a car, bending, etc.—and was used to calculate the Western Ontario and McMaster Universities Osteoarthritis Index Score.
A way to measure the extent of the healing of rickets. This score uses a 7-point scale to rank the healing of rickets and can range from -3=severe worsening to 0=no change to +3=near/complete healing. An RGI-C global score of +2.0 means a substantial healing of rickets was achieved after treatment. This score is complementary to RSS.
A softening and weakening of the bones in children caused by deficiencies in vitamin D, calcium, or phosphate at the cartilage of growth plates in children.
Amount of phosphorus in the blood. Although not part of a comprehensive metabolic panel, fasting serum phosphorus levels are a key indicator in diagnosing and managing XLH.
A way to measure changes in the severity of rickets. This score uses a 10-point scale to rank the severity of rickets from 0 (normal) to 10 points (severe). A lower score means reduced severity of rickets. This score is complementary to RGI-C.
A 24-item patient-reported questionnaire originally developed for use in clinical trials in patients with hip and/or knee osteoarthritis. Higher scores on WOMAC indicate worsening within pain, stiffness, and physical function dimensions.