title: Outcome of renal proximal tubular dysfunction with Fanconi syndrome caused by sodium valproate.
abstract: BACKGROUND
  Although Fanconi syndrome is rare in patients with epilepsy treated with sodium valproate (VPA), the prevalence might be higher in children with severe motor and intellectual disabilities (SMID). VPA-induced Fanconi syndrome usually has a favorable outcome, but the long-term outcome of renal tubular dysfunction in SMID patients remains unknown. The aim of this study was therefore to investigate the long-term outcome of renal proximal dysfunction in SMID children with Fanconi syndrome caused by VPA.
  
  
  METHODS
  The records of six children with SMID and Fanconi syndrome caused by VPA were retrospectively reviewed to assess long-term proximal renal tubular function after discontinuation of VPA. All six patients had intractable epilepsy and required tube feeding.
  
  
  RESULTS
  Proximal tubular dysfunction improved in almost all patients after VPA discontinuation, although abnormal uric acid reabsorption persisted in three patients. Five patients had hypocarnitinemia. After carnitine supplementation, one of these three patients with decreased ability to reabsorb uric acid had a normal serum level and improved fractional excretion of uric acid.
  
  
  CONCLUSIONS
  Secondary carnitine deficiency may cause prolonged tubular dysfunction in some SMID patients with VPA-induced Fanconi syndrome. Fanconi syndrome caused by VPA is a usually reversible dysfunction of the proximal tubules, but can be permanent. Although not effective for all patients, carnitine is recommended for patients with VPA-induced Fanconi syndrome, especially children with SMID.
authors.affiliation: Department of Pediatrics, Niigata City General Hospital, Niigata, Japan. yy.sawako@luck.ocn.ne.jp.|Department of Pediatrics, Nagaoka Institute for Severely Handicapped Children, Nagaoka, Japan. yy.sawako@luck.ocn.ne.jp.
authors.forename: Sawako
authors.initials: S
authors.lastname: Yamazaki
authors.affiliation: Department of Pediatrics, Niigata City General Hospital, Niigata, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Watanabe
authors.affiliation: Department of Pediatrics, Niigata City General Hospital, Niigata, Japan.
authors.forename: Seiichi
authors.initials: S
authors.lastname: Sato
authors.affiliation: Department of Pediatrics, Nagaoka Institute for Severely Handicapped Children, Nagaoka, Japan.
authors.forename: Hideto
authors.initials: H
authors.lastname: Yoshikawa
mesh_terms: D000927:Anticonvulsants / Q000009:adverse effects / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D004827:Epilepsy / Q000188:drug therapy; D005198:Fanconi Syndrome / Q000139:chemically induced / Q000150:complications*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007687:Kidney Tubules, Proximal / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D011379:Prognosis; D051437:Renal Insufficiency / Q000175:diagnosis / Q000209:etiology*; D012189:Retrospective Studies; D013997:Time Factors; D014635:Valproic Acid / Q000009:adverse effects* / Q000627:therapeutic use
chemical_list: D000927:Anticonvulsants; D014635:Valproic Acid
keywords: Fanconi syndrome; carnitine; kidney disease; renal tubular dysfunction; sodium valproate