Crystal deposits within the kidney tissue may occur as a consequence of genetic disorders such as primary hyperoxaluria, adenine phosphoribosyltransferase deficiency, distal renal tubular acidosis, Dent's disease, acquired diseases such as primary hyperparathyroidism, Sjögren's syndrome or intoxication with ethylene glycol which leads to renal failure due to calcium salts deposition. The gene discussed is APRT; the disease is Sjogren syndrome.