Renal stones in two children with two rare etiologies.

The incidence of urolithiasis in children has shown an increase in recent years which may be attributed to changing dietary patterns, sedentary lifestyles, and obesity. Among the various etiologies for renal stones in children, two rare entities worth mentioning are cystinuria and 2, 8-dihydroxyadenine (DHA) urolithiasis. Cystinuria is an inherited cause of nephrolithiasis which occurs due to impaired cystine reabsorption in the renal proximal tubule. 2, 8-DHA urolithiasis is an inherited autosomal recessive disease resulting in urinary stone disease secondary to deficiency of adenine phosphoribosyltransferase (APRT) activity. We describe two children who presented to our clinic with these two rare causes of stones.