Adenine phosphoribosyltransferase deficiency
| Adenine phosphoribosyltransferase deficiency | |
|---|---|
| Other names | APRT deficiency or 2,8 Dihydroxyadenine urolithiasis |
| Dihydroxyadenine, an insoluble purine | |
| Specialty | Endocrinology |
| Symptoms | Kidney and urinary tract stones, Urinary tract infections, blood in the urine, and chronic kidney disease. |
| Complications | End-stage renal disease. |
| Usual onset | Infancy to late adulthood. |
| Types | Type 1 and type 2. |
| Causes | Mutations in the APRT gene. |
| Diagnostic method | Urine microscopy and kidney stone analysis. |
| Differential diagnosis | Uric acid nephrolithiasis, Xanthinuria, and Primary hyperoxaluria. |
| Medication | Allopurinol. |
| Frequency | 0.4% to 1.2% |
Adenine phosphoribosyltransferase deficiency is a rare autosomal recessive metabolic disorder caused by mutations of the APRT gene. Adenine phosphoribosyltransferase (APRT) catalyzes the creation of pyrophosphate and adenosine monophosphate from 5-phosphoribosyl-1-pyrophosphate and adenine. Adenine phosphoribosyltransferase is a purine salvage enzyme. Genetic mutations of adenine phosphoribosyltransferase make large amounts of 2,8-Dihydroxyadenine causing urolithiasis and renal failure.
Adenine phosphoribosyltransferase deficiency has been classified into two types. Type one is caused by mutant alleles of APRT*Q0 and is found in individuals from many different countries. Type one causes a complete deficiency in vivo or in vitro. Type two adenine phosphoribosyltransferase deficiency is caused by mutant alleles of APRT*J results in a full enzyme defiency in vivo but only a partial deficiency in cell extracts. Type two is mainly seen in Japan.
APRT deficiency is often identified by the presence of dihydroxyadenine in urine and kidney stones. Other diagnostic tests for APRT deficiency include urine microscopy, kidney stone analysis, renal biopsy, APRT activity, and genetic testing. Treatment of adenine phosphoribosyltransferase deficiency includes allopurinol and can prevent kidney stones and chronic kidney disease in most patients.