title: The Aldosterone/Renin Ratio as a Diagnostic Tool for the Diagnosis of Primary Hypoaldosteronism in Newborns and Infants.
abstract: OBJECTIVE
  Primary hypoaldosteronism is a rare inborn disorder with life-threatening symptoms in newborns and infants due to an aldosterone synthase defect. Diagnosis is often difficult as the plasma aldosterone concentration (PAC) can remain within the normal range and thus lead to misinterpretation and delayed initiation of life-saving therapy. We aimed to test the eligibility of the PAC/plasma renin concentration (PRC) ratio as a tool for the diagnosis of primary hypoaldosteronism in newborns and infants. Meth ods: Data of 9 patients aged 15 days to 12 months at the time of diagnosis were collected. The diagnosis of primary hypoaldosteronism was based on clinical and laboratory findings over a period of 12 years in 3 different centers in Switzerland. To enable a valid comparison, the values of PAC and PRC were correlated to reference methods.
  
  
  RESULTS
  In 6 patients, the PAC/PRC ratio could be determined and showed constantly decreased values <1 (pmol/l)/(mU/l). In 2 patients, renin was noted as plasma renin activity (PRA). PAC/PRA ratios were also clearly decreased. The diagnosis was subsequently genetically confirmed in 8 patients.
  
  
  CONCLUSIONS
  A PAC/PRC ratio <1 pmol/mU and a PAC/PRA ratio <28 (pmol/l)/(ng/ml × h) are reliable tools to identify primary hypoaldosteronism in newborns and infants and help to diagnose this life-threatening disease faster.
authors.affiliation: Department of Endocrinology/Diabetology, University Children's Hospital Zurich, Zurich, Switzerland.
authors.forename: Beate
authors.initials: B
authors.lastname: Ruecker
authors.forename: Mariarosaria
authors.initials: M
authors.lastname: Lang-Muritano
authors.forename: Katharina
authors.initials: K
authors.lastname: Spanaus
authors.forename: Maik
authors.initials: M
authors.lastname: Welzel
authors.forename: Dagmar
authors.initials: D
authors.lastname: l'Allemand
authors.forename: Franziska
authors.initials: F
authors.lastname: Phan-Hug
authors.forename: Claudia
authors.initials: C
authors.lastname: Katschnig
authors.forename: Daniel
authors.initials: D
authors.lastname: Konrad
authors.forename: Paul-Martin
authors.initials: PM
authors.lastname: Holterhus
authors.forename: Eugen J
authors.initials: EJ
authors.lastname: Schoenle
mesh_terms: D000450:Aldosterone / Q000097:blood*; D005260:Female; D006801:Humans; D006994:Hypoaldosteronism / Q000097:blood* / Q000175:diagnosis*; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D012083:Renin / Q000097:blood*
chemical_list: D000450:Aldosterone; D012083:Renin