Primary hyperoxaluria type 1 (PH1) should be suspected in any child with a first kidney stone and in adults with recurrent stone disease or nephrocalcinosis and chronic kidney disease (CKD).
The usual biochemical indicator of PH1 is persistently and marked elevated urine oxalate (UOx) excretion > 0.5 mmol/1.73m² per day, which may be measured in any patient with suspected diagnosis of PH1 and normal renal function. Plasma oxalate may be measured in CKD.
Genetic testing should be performed in subjects with PH1 phenotype, with extension of mutation analysis to siblings and parents. Measurement of AGT enzyme activity in liver sample is needed only if genetic testing is inconclusive.
Conservative treatment should be started as soon as the diagnosis has been suggested: high fluid intake (> 3L/m² per 24h), pyridoxine, calcium oxalate crystallization inhibition (alkalization with oral potassium citrate as long as GFR is preserved).
Pre-emptive combined liver and kidney transplantation may be planned before to systemic oxalosis occurs, i.e. before CKD stage 4.
Comments by Evaluators:
Due to the absence of randomized trials in this ultrarare disease, most statements lack a real evidence base and merely reflect expert consensus.
No external reviews performed
Lacking involvement of patient groups.
Missing disclosure on support for guideline development