A rare cause of kidney disease in two siblings: transaldolase deficiency.

Transaldolase is a key enzyme in the pentose phosphate pathway, an alternative pathway for glucose metabolism. Transaldolase deficiency leads to the accumulation of metabolites such as polyols and seven-carbon sugars, particularly in urine. Transaldolase deficiency is a rare disorder with multisystem involvement, including liver dysfunction, hepatosplenomegaly, anemia, thrombocytopenia, endocrine abnormalities and dysmorphic features. We now report on two siblings with kidney involvement due to transaldolase deficiency. Kidney dysfunction is common in transaldolase deficiency and may progress to chronic kidney disease (CKD). The disease may have an early onset, but it can also progress without showing any sign of kidney impairment until adulthood. Transaldolase deficiency should be considered among the causes of proteinuria and CKD of unknown origin, and these patients should be carefully monitored for kidney function. Although the disease has been generally reported to manifest with tubular dysfunction, one of our patients had both tubular and glomerular involvement, which started at an earlier age than in her younger sister.