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.
本文报道1例以“血清和尿液尿酸水平极低”为临床表现的患者，复习相关文献考虑诊断为黄嘌呤尿症。进一步采集患者及其家系的外周血样进行黄嘌呤脱氢酶（XDH）基因测序，发现在其外显子19：c.1995_2006del12（p.His666_Gly669del）和外显子10：c.871G>T（p.Glu291*）存在复合杂合突变，而18号染色体上编码钼辅因子硫化酶基因未发现突变，确诊为遗传性Ⅰ型黄嘌呤尿症。患者父亲、儿子和女儿携带外显子19：c.1995_2006del12（p.His666_Gly669del）杂合突变，母亲携带外显子10：c.871G>T（p.Glu291*）杂合突变。XDH基因突变导致黄嘌呤氧化还原酶功能缺乏，从而阻碍了尿酸生成，使血液和尿液尿酸水平非常低或检测不到。临床可表现为血尿、肾绞痛、尿石症，甚至急性肾功能衰竭。通过本例患者的诊治和文献复习，旨在加深对嘌呤代谢及尿酸产生过程的认识，提高临床医师对低尿酸血症的诊治能力。.