title: Fanconi syndrome and severe polyuria: an uncommon clinicobiological presentation of a Gitelman syndrome.
abstract: BACKGROUND
  Gitelman syndrome is an autosomal recessive tubulopathy characterized by hypokalemia, hypomagnesemia, metabolic alkalosis and hypocalciuria. The majority of patients do not present with symptoms until late childhood or adulthood, and the symptoms are generally mild. We report here the first case of Gitelman syndrome presenting with the biological features of Fanconi syndrome and an early polyuria since the neonatal period. We discuss in this article the atypical electrolytes losses found in our patient, as well as the possible mechanisms of severe polyuria.
  
  
  METHODS
  A 6-year-old Caucasian girl was admitted via the Emergency department for vomiting, and initial laboratory investigations found hyponatremia, hypokalemia, metabolic acidosis with normal anion gap, hypophosphatemia, and hypouricemia. Urinalysis revealed Na, K, Ph and uric acid losses. Thus, the initial biological profile was in favor of a proximal tubular defect. However, etiological investigations were inconclusive and the patient was discharged with potassium chloride and phosphorus supplementation. Three weeks later, further laboratory analysis indicated persistent hypokalemia, a metabolic alkalosis, hypomagnesemia, and hypocalciuria. We therefore sequenced the SLC12A3 gene and found a compound heterozygosity for 2 known missense mutations.
  
  
  CONCLUSIONS
  Gitelman syndrome can have varying and sometimes atypical presentations, and should be suspected in case of hypokalemic tubular disorders that do not belong to any obvious syndromic entity. In this case, the proximal tubular dysfunction could be secondary to the severe hypokalemia. This report emphasizes the need for clinicians to repeat laboratory tests in undiagnosed tubular disorders, especially not during decompensation episodes.
authors.affiliation: Assistance Publique-Hôpitaux de Paris, Service de Néphrologie Pédiatrique, Centre de Référence des Maladies Rénales Héréditaires (MARHEA), Hôpital Necker-Enfants Malades, 149 rue de Sèvres, Paris 75015, France. karim.bouchireb@nck.aphp.fr.
authors.forename: Karim
authors.initials: K
authors.lastname: Bouchireb
authors.forename: Olivia
authors.initials: O
authors.lastname: Boyer
authors.forename: Lamisse
authors.initials: L
authors.lastname: Mansour-Hendili
authors.forename: Arnaud
authors.initials: A
authors.lastname: Garnier
authors.forename: Laurence
authors.initials: L
authors.lastname: Heidet
authors.forename: Patrick
authors.initials: P
authors.lastname: Niaudet
authors.forename: Remi
authors.initials: R
authors.lastname: Salomon
authors.forename: Rosa Vargas
authors.initials: RV
authors.lastname: Poussou
mesh_terms: D002648:Child; D003937:Diagnosis, Differential; D005198:Fanconi Syndrome / Q000175:diagnosis*; D005260:Female; D053579:Gitelman Syndrome / Q000150:complications / Q000175:diagnosis*; D006801:Humans; D011141:Polyuria / Q000209:etiology*
references.citation: Am J Hum Genet. 1996 Nov;59(5):1019-26
references.pmid: 8900229
references.citation: Pediatr Nephrol. 2013 Jan;28(1):65-70
references.pmid: 22990302
references.citation: Pediatr Nephrol. 2005 Jan;20(1):86-8
references.pmid: 15549407
references.citation: J Clin Invest. 1996 Apr 15;97(8):1960-8
references.pmid: 8621781
references.citation: Endocrine. 2012 Feb;41(1):53-7
references.pmid: 22169961
references.citation: Pediatr Nephrol. 2008 Jul;23(7):1177-81
references.pmid: 18386070
references.citation: J Pediatr. 1992 Jan;120(1):38-43
references.pmid: 1731022
references.citation: J Clin Invest. 1977 Sep;60(3):620-5
references.pmid: 893666
references.citation: Clin Chim Acta. 1984 Jul 31;140(3):231-8
references.pmid: 6147211
references.citation: Nat Genet. 1996 Jan;12(1):24-30
references.pmid: 8528245
references.citation: Nephron Physiol. 2004;96(3):p65-78
references.pmid: 15056980
references.citation: J Am Soc Nephrol. 2011 Apr;22(4):693-703
references.pmid: 21415153
references.citation: Int Urol Nephrol. 2011 Sep;43(3):905-7
references.pmid: 20625829
references.citation: Trans Assoc Am Physicians. 1966;79:221-35
references.pmid: 5929460
references.citation: Kidney Int. 2001 Feb;59(2):710-7
references.pmid: 11168953
references.citation: Eur J Endocrinol. 2011 Oct;165(4):665-73
references.pmid: 21753071
references.citation: Nephrol Dial Transplant. 2011 Jan;26(1):151-5
references.pmid: 20571093