X-linked Hypophosphatemia
New X-linked hypophosphatemia research, summarized each month in plain language.
2026 so far: So far in 2026 (January 2026 to September 2026), burosumab studies continued to show higher phosphate and improved rickets measures. Longer follow-up raised monitoring questions, and symptom improvements were not the same across all measures. Read the 2026 review
We also cover clinical trials.
Yearly update
2026 so far
- Burosumab in routine care. More real-world follow-up connected phosphate gains to symptoms.
- Pain and daily life. Reports clarified pain patterns and persistent adult burden.
- Key monitoring signals. Short-term markers aligned; longer-term PTH questions surfaced.
- Genetic answers and access. Reports showed missed variants and uneven testing availability.
- Teeth and bone tests. Reports clarified tooth-structure changes that may help explain dental problems, alongside mixed bone-scan signals.
New
September 2026
- Burosumab outcomes. In adults, burosumab was linked with better pain and function.
- Rickets lab marker. In children, alkaline phosphatase closely matched x-ray rickets changes.
- Hospital stay patterns. In national data, rare bone disease admissions, as a group including XLH, had longer, more intensive stays.
August 2026
- Bone density by site. Spine and forearm bone density results differed by scan site.
- Inner bone strength. High-detail scans suggested weaker inner bone near the ankle.
- Pregnancy case report. One burosumab pregnancy report found no clear drug-related early problems, but unusual newborn labs.
- Tooth structure changes. Dentin and pulp changes may help explain infections and tooth loss.
July 2026
- Child burosumab effects. Phosphate levels and rickets X-ray scores improved over about a year.
- Parathyroid hormone rise. Parathyroid hormone increased over three years in some children.
- Adult symptoms burden. Adults with little treatment often had pain, joint, and dental problems.
June 2026
- PHEX gene finding. Exome testing found a PHEX change, supporting an XLH diagnosis.
- 6-month follow-up. One child had partial X-ray healing with ongoing blood tests.
- Team-based care. Clinicians emphasized lifelong, coordinated care across specialties.
May 2026
- New PHEX variant. One case report linked XLH to a newly described PHEX gene change involving a partial LINE-1 DNA insertion.
- Leg and dental findings. In the same child, the report described leg deformities and a dental abscess alongside the genetic finding.
- Burosumab in another FGF-23 disorder. A separate single-patient report (not XLH) found that burosumab increased blood phosphate in McCune-Albright syndrome with FGF-23–related phosphate wasting.
April 2026
- Burosumab and phosphate. Blood phosphate levels often increased after starting burosumab and stayed higher over time.
- Pain prescriptions. Prescription pain-medication use was common before burosumab and often changed little after starting it.
- Adult daily impact. In adult groups, quality-of-life scores were often below typical population norms, and bone and dental problems were commonly reported.
- Bone activity markers. In some studies, blood markers linked to bone activity often remained outside the usual range during burosumab treatment.
March 2026
- Faster growth with burosumab. In routine care studies, children on burosumab were linked with faster growth than children not receiving burosumab.
- Fasting may not be required. In a small substudy, phosphate and calcium results on burosumab were similar whether blood was drawn fasting or after a meal.
- Dental changes may persist. Some tooth mineral and gum-support problems may only partly improve with standard XLH therapy.
February 2026
- Bone age delay and lab activity. In children with XLH, bone age often lagged behind calendar age (especially in boys), and larger delays tended to occur alongside lab signs of more active bone disease.
- How close height predictions were. Two common adult-height prediction methods were usually close to final or near-final adult height, with small sex-related differences in which method tended to overestimate.
- Pregnancy after stopping burosumab. One detailed case report described a term pregnancy after stopping burosumab with no complications reported, and it noted that calcium balance can shift late in pregnancy as well as phosphate.
- Finding tumors that mimic XLH labs. When an acquired FGF23-producing tumor is suspected, combining scan review with vein blood sampling localized tumors more often in a study of tumor-caused FGF23 excess.
January 2026
- Adult burosumab results. Phosphate increased, with less pain and better physical function.
- Burosumab in infants. Phosphate increased, but did not fully return to normal.
- Types of pain. Nerve-like or unclear pain linked to worse sleep and mood.
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