Patient Stories
“It’s just this lovely surprise of being able to make it to ladies’ night or to walk my dog.”
—Aly, age 41
“Just the fact that I’m able to participate in life
more has been a gift.”
—Karen, age 40
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CRYSVITA PROPOSED MECHANISM OF ACTION VIDEO
Connect with a community of support for X-linked hypophosphatemia (XLH)
Ultragenyx sponsored
CRYSVITA Educational Events for Patients and Caregivers
The CRYSVITA Educational Events program offers events that are presented by an XLH specialist. These events provide opportunities to connect with local members in the XLH community and learn more about CRYSVITA for XLH.
XLH Network
The XLH Network is a global patient support organization for people with XLH, parents, and caregivers. The website contains educational resources about XLH for patients and medical professionals.
NIH Genetic and Rare Diseases Information Center (GARD)
GARD maintains a list of rare diseases and related terms to help people find reliable information about their disease.
National Organization for Rare Disorders (NORD)
NORD is a patient advocacy organization dedicated to individuals with rare diseases and the organizations that serve them.
Glossary
bone histomorphometry:
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.
conventional therapy:
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.
fibroblast growth factor 23 (FGF23):
A protein that plays a role in phosphate homeostasis. In XLH, the excess circulating FGF23 leads to increased
signaling, resulting in impaired phosphate uptake.
least squares (LS) mean:
A statistic for the estimate of the mean after adjusting for the effect of other variables in a study.
mineralization lag time (MLt):
The interval between osteoid formation and osteoid mineralization. In XLH, mineralization lag times are long, pointing to abnormalities in the process of bone mineralization.
osteoid:
An unmineralized organic tissue that eventually undergoes calcification and is deposited as lamellae or layers in the bone matrix.
osteoid thickness (O.Th):
A measurement of the amount of unmineralized bone.
osteoid volume to bone volume (OV/BV):
A ratio of unmineralized bone to mineralized bone. In XLH, this ratio is large, pointing to a greater presence of
unmineralized bone.
Glossary2
osteomalacia:
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.
PHEX gene:
Phosphate-regulating endopeptidase homolog X-linked. Variants in this gene cause X-linked hypophosphatemic rickets.
physical function:
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.
Radiographic Global Impression of Change (RGI-C):
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.
rickets:
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.
serum phosphorus:
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.
Thacher Rickets Severity Score (RSS):
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.
Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC):
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.
