Background: Approximately 10% of the cases with primary hyperoxaluria type I present before age 1 and are usually classified as neonatal primary oxaluria.
Case reports: Four unrelated infants, aged 3 to 9 months, were admitted for severe renal failure due to primary hyperoxaluria type I. Other affected members were known in two of these four families but the disease was not present at the same age in each family. Echogenicity of kidneys was increased in all the patients and calcium oxalate crystals were seen in the collecting system and within the renal parenchyma. Urolithiasis was not present. Treatment of renal failure, ie, peritoneal dialysis, was uneffective in one patient and was interrupted in two others because organ transplantation was impossible.
Conclusions: The infantile forms of primary hyperoxaluria type I may be rapidly complicated by severe renal failure in the absence of urolithiasis.