title: Recurrent exercise-induced acute kidney injury by idiopathic renal hypouricemia with a novel mutation in the SLC2A9 gene and literature review.
abstract: BACKGROUND
  Idiopathic renal hypouricemia (iRHUC) is an autosomal recessive hereditary disorder, characterized by impaired tubular uric acid transport, re-absorption insufficiency and/or the acceleration of secretions. Some patients present with severe complications, such as exercise-induced acute kidney injury (EIAKI) and nephrolithiasis.
  
  
  METHODS
  Herein, we report the case of a girl with severe iRHUC (serum urate 0.05 mg/dL, fractional excretion of uric acid 295.99%) associated with recurrent EIAKI, in whom the disease was caused by a homozygous mutation (g.68G > A in exon 3) in the SLC2A9 gene. Her family members (father, mother and brother) carried the same mutation but were heterozygous, without any signs of severe hypouricemia.
  
  
  CONCLUSIONS
  Our findings indicate that iRHUC is a rare disorder but that it should also be considered in patients with EIAKI, especially in those patients who manifest with moderately elevated or normal serum concentrations of uric acid during the acute phase of AKI. Mutational screening of the SLC2A9 gene is necessary for the diagnosis of iRHUC, and homozygous mutations of the SLC2A9 alleles can cause severe hypouricemia. Careful attention should be paid to any signs of hypouricemia during the recovery phase of AKI and long-term follow-up.
authors.forename: Huijun
authors.initials: H
authors.lastname: Shen
authors.forename: Chunyue
authors.initials: C
authors.lastname: Feng
authors.forename: Xia
authors.initials: X
authors.lastname: Jin
authors.affiliation: Department of Nephrology, The Children's Hospital of Zhejiang University School of Medicine, Hangzhou 310003, Zhejiang Province, China. maojh88@126.com.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Mao
authors.forename: Haidong
authors.initials: H
authors.lastname: Fu
authors.forename: Weizhong
authors.initials: W
authors.lastname: Gu
authors.forename: Ai'min
authors.initials: A
authors.lastname: Liu
authors.forename: Qiang
authors.initials: Q
authors.lastname: Shu
authors.forename: Lizhong
authors.initials: L
authors.lastname: Du
mesh_terms: D058186:Acute Kidney Injury / Q000209:etiology* / Q000235:genetics; D002648:Child; D015444:Exercise; D005260:Female; D051246:Glucose Transport Proteins, Facilitative / Q000235:genetics*; D006801:Humans; D009154:Mutation; D010375:Pedigree; D012008:Recurrence; D015499:Renal Tubular Transport, Inborn Errors / Q000150:complications*; D014545:Urinary Calculi / Q000150:complications*
chemical_list: D051246:Glucose Transport Proteins, Facilitative; C411811:SLC2A9 protein, human