[Analysis of a family with hypouricemia due to type Ⅰ xanthinuria]

This article reports a patient presenting with"extremely low uric acid levels in blood and urine"clinically along with reviewing relevant literature to consider a diagnosis of xanthinuria. Peripheral blood samples of the patient and her family were further collected for xanthine dehydrogenase(XDH) gene sequencing, showing that the patient had compound heterozygous mutations in exon 19:c.1995_2006del12(p.His666_Gly669del) and exon 10:c.871G>T(p.Glu291*), however no mutations were found in the gene encoding MOCOS on chromosome 18, confirming the diagnosis of hereditary xanthinuria type Ⅰ.The patient's father, son and daughter carried heterozygous mutations in exon 19:c.1995_2006del12(p.His666_Gly669del), and the mother carried heterozygous mutations in exon 10:c.871G>T(p.Glu291*).Mutations in the XDH gene cause a lack of xanthine oxidoreductase function, which hinders the production of uric acid, leading to very low or undetectable levels in blood and urine. Patients present clinically with hematuria, renal colic, urolithiasis, and even acute renal failure. Through the diagnosis and treatment of this patient and literature review, the article aims to deepen the understanding of purine metabolism and uric acid production process, and improve the clinicians' diagnosis and treatment ability of hypouricemia.