Doctors found a woman with a rare genetic bone disease called X-linked hypophosphatemia (XLH) who also had an unusual genetic variation affecting her kidneys. When she received the standard treatment for her bone disease over many years, it caused serious problems with calcium and minerals in her kidneys, leading to kidney stones and severe bone pain. A newer treatment called burosumab helped improve her symptoms and allowed her to walk again after being in a wheelchair. This case shows that people with XLH who have certain kidney issues may need different treatment approaches to avoid complications.
The Quick Take
- What they studied: How a rare bone disease interacts with a kidney genetic variation, and whether a newer treatment works better than traditional therapy
- Who participated: One 28-year-old woman diagnosed with the bone disease at 18 months old who also carried an unusual kidney gene variant
- Key finding: The standard long-term treatment for the bone disease may have worsened kidney problems in this patient, but a newer drug called burosumab improved her symptoms and allowed her to regain the ability to walk independently
- What it means for you: If you have this rare bone disease, especially with kidney issues, doctors may need to monitor you more carefully and consider newer treatment options. This is not medical advice—talk to your doctor about what’s best for your specific situation
The Research Details
This is a case report, which means doctors documented the medical history and treatment of one specific patient. The patient was a woman who was diagnosed with X-linked hypophosphatemia (XLH), a rare genetic bone disease, when she was 18 months old. She also had an unusual genetic variation in a gene called CLDN16 that affects how kidneys handle minerals. The doctors tracked her medical care over many years, noting what treatments she received, what side effects developed, and how she responded to a newer medication called burosumab. They reviewed her blood test results, imaging studies, and surgical records to understand how her conditions developed and changed over time.
Case reports are important because they describe unusual situations that doctors might not see often. By carefully documenting this patient’s experience, doctors can learn about unexpected complications and discover whether new treatments might work better. This information helps other doctors recognize similar patterns in their own patients and make better treatment decisions.
This is a single case report, so the findings apply only to this one patient and cannot be generalized to all people with this disease. However, the detailed medical documentation provides valuable insights. The case was published in a medical journal, meaning other experts reviewed it. The main limitation is that we cannot know if other patients would have the same experience or if the improvements were due to the new medication, surgery, or other factors.
What the Results Show
The patient had severe bone pain and was unable to walk without a wheelchair before treatment with burosumab. After surgery to remove part of her parathyroid gland and starting the newer medication burosumab, her pain improved significantly and she regained the ability to walk independently. Blood tests showed improvements in phosphate levels, alkaline phosphatase (an enzyme related to bone health), and parathyroid hormone levels, though these did not completely return to normal. The patient had developed kidney stones (medullary nephrocalcinosis) from years of standard phosphate treatment, which may have contributed to her severe symptoms. The combination of the bone disease and the kidney gene variation appears to have made her more vulnerable to complications from the standard treatment.
The patient’s kidney function showed signs of renal tubular acidosis, a condition where the kidneys cannot properly balance acids in the body. This kidney problem may have made it harder for her body to handle the minerals from her standard treatment. The incomplete normalization of blood test results after treatment suggests that the kidney damage from years of standard therapy may have lasting effects. The case demonstrates that the newer medication burosumab can help even when kidney complications are present.
Standard treatment for XLH has traditionally involved giving phosphate supplements and active vitamin D for many years. This case suggests that while this treatment helps bones in the short term, it may cause serious kidney problems in some patients, especially those with underlying kidney vulnerabilities. The newer medication burosumab works differently by targeting the root cause of the disease rather than just replacing missing minerals. Previous research showed that people carrying the CLDN16 gene variation usually have no symptoms, but this case shows that when combined with XLH and long-term phosphate therapy, problems can develop.
This report describes only one patient, so we cannot know if other patients would have the same experience. We cannot be certain whether the improvements came from the surgery, the new medication, or a combination of both. The patient’s kidney problems developed over many years of treatment, so we cannot say exactly when or why they started. Without comparing this patient to others with similar conditions, we cannot determine how common these complications are. The case was documented after the fact, so some details about her early treatment may not be complete.
The Bottom Line
People with X-linked hypophosphatemia should work closely with their doctors to monitor kidney function regularly, especially if they have been on long-term phosphate and vitamin D treatment. Newer medications like burosumab may be worth discussing with your doctor as an alternative or addition to traditional treatment, particularly if you develop kidney complications. Regular blood tests and imaging to check for kidney stones are important. This case suggests that a one-size-fits-all approach may not work for everyone with this disease. (Confidence: Low to Moderate—based on one patient’s experience)
People diagnosed with X-linked hypophosphatemia should be aware of this case, especially if they have had long-term phosphate treatment or develop kidney problems. Family members of people with this disease may want to discuss genetic testing. Doctors treating patients with rare bone diseases should consider whether patients have underlying kidney vulnerabilities. People with CLDN16 gene variations who develop bone disease symptoms should alert their doctors to this combination. People without this disease do not need to apply these findings to their own health.
The patient in this case had been receiving standard treatment for over 25 years before developing severe complications. Improvements from burosumab and surgery were noticed within weeks to months, with the ability to walk returning relatively quickly. However, complete normalization of blood test results took longer and was incomplete even after several months of the new treatment. Benefits from treatment changes may take weeks to months to become noticeable, but full recovery may take longer or may not be complete.
Want to Apply This Research?
- Track weekly bone pain levels (0-10 scale) and mobility status (able to walk independently, need assistance, wheelchair dependent) to monitor treatment effectiveness over time
- Set reminders for regular blood work appointments to monitor phosphate, alkaline phosphatase, and parathyroid hormone levels; log any new symptoms like kidney pain or changes in urination
- Create a monthly summary comparing pain levels, mobility, and lab results to identify trends and share with your healthcare team; track any new medications or treatment changes and their timing relative to symptom changes
This case report describes the experience of one patient and should not be used to diagnose or treat any condition. X-linked hypophosphatemia is a rare genetic disease that requires specialized medical care. If you or a family member has been diagnosed with this condition or suspect you might have it, consult with a qualified physician or genetic specialist. Do not change your current treatment without discussing it with your doctor. The findings in this case may not apply to other patients. Always seek professional medical advice before making any health decisions.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.