May 2026 Research Update

This month added a detailed look at what a kidney-only transplant can look like for primary hyperoxaluria type 1 (PH1) when oxalate-lowering RNA interference treatment (lumasiran) is continued. The report described encouraging early kidney graft function, while also showing that oxalate-related problems such as new stones and crystal deposits can still happen after transplant and may flare when complications like rejection occur. [1]

In the featured patient, kidney function was strong in the first year after transplant and blood oxalate levels dropped, but imaging later showed a small kidney stone and gravel-like deposits in the transplanted kidney. After a rejection episode, kidney function and blood oxalate worsened and a partially blocking stone was noted, illustrating how setbacks can affect oxalate control and stone risk even when lumasiran is used. [1]

Across the additional published kidney-only transplant cases reviewed in the same paper, kidney stones and stent blockage were each reported in about 20% of cases, and mild oxalate crystal deposits in the graft were described in a sizeable minority. The same report also noted that oxalate in the eyes (ocular oxalosis) could persist after transplant, even when kidney function was largely preserved. [1]

For patients and caregivers, this is early but practical evidence about what can go well and what can still go wrong when lumasiran is paired with a kidney-only transplant. It may matter now mainly for understanding expectations: early graft function and lower oxalate levels were possible, but stones, crystal deposits, and rejection were still part of the reported experience, meaning follow-up testing and imaging remained important in these reports. What remains uncertain is how often these outcomes happen over the long term and which monitoring approach best predicts problems, because the evidence here is based on one detailed case plus a small set of published cases. [1]

This month, the new reports reinforced that primary hyperoxaluria type 1 can sometimes show up in unexpected or hard-to-manage ways beyond typical kidney stone patterns. One case highlighted an unusual kidney stone pattern involving both kidneys, and another report in siblings showed that oxalate can build up in the heart and be seen on imaging or confirmed on tissue examination. Together, these reports broaden the picture of how PH1 can affect different organs, especially when kidney function is impaired. [2] [3]

One case described bilateral staghorn calculi, meaning large branching stones that fill parts of the kidney collecting system, as a presenting feature in PH1. The report mainly served as a reminder that PH1-related stones can sometimes be extensive and affect both kidneys at the same time. [2]

In a separate case series of two siblings, heart involvement was documented with heart tests and imaging, and in one sibling oxalate deposits were confirmed in heart tissue at autopsy. The other sibling had signs of heart strain on testing and later started lumasiran, with no adverse events reported in that individual during the described period. [3]

For patients, these are individual reports, so they cannot predict what will happen for most people with PH1. They may matter now by helping families recognize that PH1 can sometimes involve more than kidney stones, including possible heart involvement in some situations, and that stone patterns can be unusually extensive. What remains uncertain is how common these presentations are and which people are most at risk, because the evidence comes from a small number of patients rather than larger studies. [2] [3]