Primary hyperoxaluria is caused by inherited deficiencies in enzymes that normally metabolize glyoxylate, a precursor compound that is converted to oxalate when these enzymatic pathways fail. Three genetically distinct subtypes (types 1, 2, and 3) each involve a different enzyme and metabolic pathway, yet share the common consequence of oxalate overproduction. No specific causative gene is certified in the primary known_genes field of this packet for the umbrella condition. The hereditary basis of the disorder means it can affect multiple family members, and the condition may be more common in families or communities where there is shared ancestry and a higher probability that both parents carry the same rare variant. The clinical severity of all subtypes is influenced by the extent to which oxalate overproduction exceeds the kidneys' capacity for excretion.

Primary hyperoxaluria is suspected in individuals with recurrent calcium oxalate kidney stones or nephrocalcinosis, particularly when associated with progressive kidney dysfunction or a family history of similar findings. Laboratory evaluation of oxalate excretion is central to diagnosis: in those with preserved kidney function, measurement of urinary oxalate in 24-hour urine collections is the primary approach; when kidney function is significantly reduced, plasma oxalate concentration becomes the preferred measure. Kidney stone composition showing 100% calcium oxalate monohydrate is a supportive finding. Imaging studies, including kidney ultrasound, assess stone burden and the extent of nephrocalcinosis. Genetic testing provides definitive molecular diagnosis and establishes the specific subtype, which has implications for management and transplantation decisions. Diagnosis may be delayed because the condition presents across a wide age range and can mimic more common kidney stone disorders.

The FDA-approved treatment certified in this packet for primary hyperoxaluria is nedosiran (Rivfloza), an RNA interference (RNAi) therapeutic agent that reduces hepatic oxalate production by targeting lactate dehydrogenase A. This treatment is approved for primary hyperoxaluria type 1 in individuals aged two years and older with sufficient kidney function. Management approaches described in the GeneReviews chapter for primary hyperoxaluria type 1 encompass both targeted therapies and supportive care strategies. Organ transplantation, specifically liver and kidney transplantation performed simultaneously or sequentially, represents a curative approach for type 1 by restoring normal hepatic enzyme function; kidney transplantation alone addresses renal function but does not correct the underlying metabolic cause. Maintaining high fluid intake and urine volume is a central supportive measure across all subtypes, aimed at reducing calcium oxalate supersaturation in the urinary tract. As kidney function declines, individuals require evaluation and management for potential systemic oxalate deposition affecting multiple organ systems. Patient financial assistance is available through an accepting program for individuals with primary hyperoxaluria.

The natural history of untreated or inadequately managed primary hyperoxaluria involves progressive decline in kidney function from the combined effects of nephrolithiasis complications and nephrocalcinosis. In the most severe infantile-onset presentations, progression to ESKD can occur within the first year of life. Systemic oxalate deposition affecting multiple organ systems follows when kidney clearance is severely compromised. Prognosis varies considerably by subtype and age at onset, with infantile-onset forms historically associated with the highest morbidity and mortality. Outcomes have improved with earlier diagnosis, advances in supportive care, and the availability of targeted RNAi therapeutic agents that reduce hepatic oxalate generation. The clinical trajectory is significantly influenced by how early intervention is initiated and how effectively kidney function is preserved.

Several certified active trial records are present for primary hyperoxaluria, including investigations of gene editing approaches targeting glyoxylate metabolic pathways in primary hyperoxaluria type 1. Active clinical trials for this condition are listed on ClinicalTrials.gov.