title: Case report: severe asymptomatic hyponatremia in Prader-Willi Syndrome.
abstract: BACKGROUND
  Prader-Willi syndrome is a complex neurogenetic, multisystem disorder. Despite the variable endocrine abnormalities and hypothalamic-pituitary axis dysfunction, hyponatremia has been reported in only a few PWS patients. In previously reported PWS individuals, hyponatremia was associated with abnormal fluid intake or during desmopressin treatment.
  
  
  METHODS
  We describe an infant with Prader-Willi syndrome who had severe, prolonged asymptomatic hyponatremia without a history of excessive fluid intake or desmopressin treatment. We compare the findings with those of the few other reported cases and describe, for the first time, results of a hypertonic saline infusion test and studies of adrenal cortical function.
  
  
  CONCLUSIONS
  Hyponatremia should be suspected in children with Prader-Willi syndrome, especially in infants with severe failure to thrive. Further studies are needed to determine the pathophysiology of hyponatremia in this syndrome.
authors.affiliation: Department of Pediatrics B, Schneider Children's Medical Center of Israel, Petach Tikva, Israel and Faculty of Health Sciences, Ben-Gurion University, Beer Sheva, Israel.
authors.forename: Daniel
authors.initials: D
authors.lastname: Landau
authors.affiliation: Neuropediatric Unit, Department of Pediatrics, Shaare Zedek Medical Center, P.O.B 3235, Jerusalem, 91031, Israel. hirschmd@gmail.com.
authors.forename: Harry J
authors.initials: HJ
authors.lastname: Hirsch
authors.affiliation: Neuropediatric Unit, Department of Pediatrics, Shaare Zedek Medical Center, P.O.B 3235, Jerusalem, 91031, Israel.|The Faculty of Medicine, the Hebrew University, Jerusalem, Israel.
authors.forename: Varda
authors.initials: V
authors.lastname: Gross-Tsur
mesh_terms: D058070:Asymptomatic Diseases; D006801:Humans; D007010:Hyponatremia / Q000175:diagnosis / Q000209:etiology*; D007223:Infant; D008297:Male; D011218:Prader-Willi Syndrome / Q000150:complications* / Q000175:diagnosis