title: A clinical phenotype mimicking essential hypertension in a newly discovered family with Liddle's syndrome.
abstract: BACKGROUND
  Liddle's syndrome (LS) is a monogenic form of hypertension simulating a mineralocorticoid excess, and is currently suspected in young hypokalemic hypertensives. The aims of the study were: (i) to evaluate the clinical phenotype of LS in a newly identified Italian family of Sicilian origin carrying a gain-of-function mutation of the β subunit of the epithelial sodium channel (ENaC) (P617L) previously reported by our group in an apparently unrelated Sicilian patient presenting the typical phenotype of LS including hypokalemia; (ii) to determine whether an unknown biological relationship exists between the newly identified family and the family of the proband previously reported.
  
  
  METHODS
  Genetic analysis was performed in the present family, in the individual in which the βP617L mutation was first observed, and in his relatives.
  
  
  RESULTS
  βP617L mutation was identified in the proband and in three maternal relatives. None of them showed hypokalemia. Mild to severe early onset hypertension and left ventricular hypertrophy were present in all of them. Analysis of mitochondrial DNA (mtDNA) and Y chromosome profiles in the present family and in the proband's family previously reported showed the absence of a relationship between them. The availability of only one carrier of the mutation in one of the two families meant that a genetic analysis able to assess a founder effect was not feasible.
  
  
  CONCLUSIONS
  LS should be considered in all cases of early onset hypertension, independently of the plasma potassium concentration. The incidence of LS may be greater than is currently thought, because hypokalemia is not invariably present.
authors.affiliation: Second Unit of Internal Medicine, Department of Internal Medicine, Santa Maria Nuova Hospital, Reggio Emilia, Italy. rossi.ermanno@asmn.re.it
authors.forename: Ermanno
authors.initials: E
authors.lastname: Rossi
authors.forename: Enrico
authors.initials: E
authors.lastname: Farnetti
authors.forename: Davide
authors.initials: D
authors.lastname: Nicoli
authors.forename: Marco
authors.initials: M
authors.lastname: Sazzini
authors.forename: Franco
authors.initials: F
authors.lastname: Perazzoli
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Regolisti
authors.forename: Chiara
authors.initials: C
authors.lastname: Grasselli
authors.forename: Rosaria
authors.initials: R
authors.lastname: Santi
authors.forename: Aurelio
authors.initials: A
authors.lastname: Negro
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Mazzeo
authors.forename: Franco
authors.initials: F
authors.lastname: Mantero
authors.forename: Donata
authors.initials: D
authors.lastname: Luiselli
authors.forename: Bruno
authors.initials: B
authors.lastname: Casali
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000450:Aldosterone / Q000378:metabolism; D000584:Amiloride / Q000627:therapeutic use; D053503:Epithelial Sodium Channels / Q000235:genetics*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy / Q000235:genetics*; D007008:Hypokalemia / Q000235:genetics; D056929:Liddle Syndrome / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D012150:Polymorphism, Restriction Fragment Length; D012083:Renin / Q000378:metabolism
chemical_list: D053503:Epithelial Sodium Channels; D000450:Aldosterone; D000584:Amiloride; D012083:Renin