Xanthinuria: A Rare Case Report

Abstract

INTRODUCTION: Classical xanthinuria is an autosomal recessive hereditary disease which manifests as a result of deficiency of xanthine dehydrogenase which converts hypoxanthine, and xanthine into uric acid. Molybdenum cofactor deficiency, an inherited form of xanthinuria, causes hyperreflexia, microcephaly, and other central nervous system symptoms in newborns. Molybdenum cofactor deficiency, an inherited form of xanthinuria, causes hyperreflexia, microcephaly, and other central nervous system symptoms in newborns. The function of three different enzymes (xanthine dehydrogenase, aldehyde oxidase, and sulfite oxidase) depends on a molybdenum-containing cofactor that is congenitally defective in this disorder. CASE REPORT: A full term female baby born to a G3P1L1A1 mother via normal vaginal delivery was referred from outside hospital on day of life 10 in view of one episode of convulsion on day 3 of life. Baby was screened for inborn errors of metabolism which revealed increased excretion of Xanthine in urine. MRI of brain was done which showed extensive areas of diffusion restriction involving bilateral cerebral hemispheres, bilateral corticospinal tracts and corpus callosum suggestive of Acute hypoxic ischaemic encephalopathy. DISCUSSION: Because of enzymatic deficiency, xanthine dehydrogenase cannot be converted into uric acid which leads to increase in blood levels, and urinary excretion of hypoxanthine, and xanthine. Since these substances have a lower solubility in urine, they accumulate in the urinary system leading to formation of stones. Reduced or undetectable serum uric acid levels associated with MoCD are a result of the deficiency of xanthine dehydrogenase. Most of the patients with classical xanthinuria are asymptomatic, and in 30% of the cases urolithiasis develops. CONCLUSION: Refractory seizures, encephalopathy, and the absence of radiologic signs of HIE a positive family history of perinatal asphyxia, and refractory seizures are contributors in newborn fatalities that demonstrate a significant tendency to develop xanthinuria. A thorough research regarding its prevalence and prognosis should be done. Keywords: xanthinuria, autosomal recessive hereditary disease, newborn