Nephrolithiasis in twins with APRT-deficiency. Stones as a marker of an inborn error of metabolism.

We describe the first case of twins with complete APRT-deficiency, indicating homozygosity, and 2.8-dihydroxyadenine stones in both kidneys. The stones were discovered accidentally during a routine abdominal ultrasound examination, and thus the diagnosis of an inborn error of metabolism, was established. In nephrolithiasis caused by an inborn error of metabolism, early diagnosis and therapy are of great importance for prognosis and quality of life.