title: Apparent Mineralocorticoid Excess by a Novel Mutation and Epigenetic Modulation by HSD11B2 Promoter Methylation.
abstract: BACKGROUND
  Apparent mineralocorticoid excess (AME) is a rare autosomal recessive disease resulting from mutations within the hydroxysteroid (11β-dehydrogenase2 [HSD11B2]) gene causing a prominent mineralocorticoid receptor activation by cortisol and hypokalemic low renin hypertension as the main clinical feature.
  
  
  OBJECTIVE
  The objective of the study was to characterize AME for possible novel HSD11B2 mutations and to define the role of HSD11B2 promoter methylation in the phenotypic expression of the disease.
  
  
  METHODS
  Two proband brothers and 10 relatives participated in the study.
  
  
  METHODS
  Peripheral blood mononuclear cell DNA was used for HSD11B2 exon sequencing, and a new predicted structure of 11β-hydroxysteroid dehydrogenase type 2 was generated by an in silico three-dimensional modeling. Promoter methylation was determined by bisulfite pyrosequencing. Urinary tetrahydrocortisol plus allotetrahydrocortisol to tetrahydrocortisone ratio, a surrogate marker of 11β-hydroxysteroid dehydrogenase type 2 activity, was measured by gas chromatography-mass spectrometry.
  
  
  RESULTS
  A novel homozygous variant at HSD11B2 exon 3 site (c.C662G) resulting in an alanine-to-glycine change at position 221 was discovered by sequencing the DNA of the probands. A monoallelic mutation was found in the DNA of the parents and other four relatives. In silico three-dimensional modeling showed that the Ala221Gly substitution could perturb a hydrophobic interaction by reducing the enzymatic affinity for the substrate. The HSD11B2 promoter methylation of normotensive heterozygous relatives was similar to that of wild types, whereas the hypertensive heterozygous subjects showed higher methylation than wild types, consistently with a transcriptional repressive effect of promoter hypermethylation.
  
  
  CONCLUSIONS
  A novel HSD11B2 functional mutation accounting for an Ala221Gly substitution causes AME. The hypertension phenotype is also epigenetically modulated by HSD11B2 methylation in subjects heterozygous for the mutation.
authors.affiliation: Departments of Medicine (F.P., S.F., F.M., C.Z., S.U., O.O.) Life and Reproduction Sciences (F.A., A.Ga., P.C.), Pathology and Diagnostics (G.S.), and Biotechnology (A.Gi., G.S.), University of Verona, 37134 Verona, Italy; Chaum Life Center (S.-W.C.), CHA University, 135-081 Seoul, Korea; and Friedman School of Nutrition Science and Policy (S.-W.C.), Tufts University, Boston, Massachusetts 02111.
authors.forename: Francesca
authors.initials: F
authors.lastname: Pizzolo
authors.affiliation: Departments of Medicine (F.P., S.F., F.M., C.Z., S.U., O.O.) Life and Reproduction Sciences (F.A., A.Ga., P.C.), Pathology and Diagnostics (G.S.), and Biotechnology (A.Gi., G.S.), University of Verona, 37134 Verona, Italy; Chaum Life Center (S.-W.C.), CHA University, 135-081 Seoul, Korea; and Friedman School of Nutrition Science and Policy (S.-W.C.), Tufts University, Boston, Massachusetts 02111.
authors.forename: Simonetta
authors.initials: S
authors.lastname: Friso
authors.affiliation: Departments of Medicine (F.P., S.F., F.M., C.Z., S.U., O.O.) Life and Reproduction Sciences (F.A., A.Ga., P.C.), Pathology and Diagnostics (G.S.), and Biotechnology (A.Gi., G.S.), University of Verona, 37134 Verona, Italy; Chaum Life Center (S.-W.C.), CHA University, 135-081 Seoul, Korea; and Friedman School of Nutrition Science and Policy (S.-W.C.), Tufts University, Boston, Massachusetts 02111.
authors.forename: Francesca
authors.initials: F
authors.lastname: Morandini
authors.affiliation: Departments of Medicine (F.P., S.F., F.M., C.Z., S.U., O.O.) Life and Reproduction Sciences (F.A., A.Ga., P.C.), Pathology and Diagnostics (G.S.), and Biotechnology (A.Gi., G.S.), University of Verona, 37134 Verona, Italy; Chaum Life Center (S.-W.C.), CHA University, 135-081 Seoul, Korea; and Friedman School of Nutrition Science and Policy (S.-W.C.), Tufts University, Boston, Massachusetts 02111.
authors.forename: Franco
authors.initials: F
authors.lastname: Antoniazzi
authors.affiliation: Departments of Medicine (F.P., S.F., F.M., C.Z., S.U., O.O.) Life and Reproduction Sciences (F.A., A.Ga., P.C.), Pathology and Diagnostics (G.S.), and Biotechnology (A.Gi., G.S.), University of Verona, 37134 Verona, Italy; Chaum Life Center (S.-W.C.), CHA University, 135-081 Seoul, Korea; and Friedman School of Nutrition Science and Policy (S.-W.C.), Tufts University, Boston, Massachusetts 02111.
authors.forename: Chiara
authors.initials: C
authors.lastname: Zaltron
authors.affiliation: Departments of Medicine (F.P., S.F., F.M., C.Z., S.U., O.O.) Life and Reproduction Sciences (F.A., A.Ga., P.C.), Pathology and Diagnostics (G.S.), and Biotechnology (A.Gi., G.S.), University of Verona, 37134 Verona, Italy; Chaum Life Center (S.-W.C.), CHA University, 135-081 Seoul, Korea; and Friedman School of Nutrition Science and Policy (S.-W.C.), Tufts University, Boston, Massachusetts 02111.
authors.forename: Silvia
authors.initials: S
authors.lastname: Udali
authors.affiliation: Departments of Medicine (F.P., S.F., F.M., C.Z., S.U., O.O.) Life and Reproduction Sciences (F.A., A.Ga., P.C.), Pathology and Diagnostics (G.S.), and Biotechnology (A.Gi., G.S.), University of Verona, 37134 Verona, Italy; Chaum Life Center (S.-W.C.), CHA University, 135-081 Seoul, Korea; and Friedman School of Nutrition Science and Policy (S.-W.C.), Tufts University, Boston, Massachusetts 02111.
authors.forename: Alberto
authors.initials: A
authors.lastname: Gandini
authors.affiliation: Departments of Medicine (F.P., S.F., F.M., C.Z., S.U., O.O.) Life and Reproduction Sciences (F.A., A.Ga., P.C.), Pathology and Diagnostics (G.S.), and Biotechnology (A.Gi., G.S.), University of Verona, 37134 Verona, Italy; Chaum Life Center (S.-W.C.), CHA University, 135-081 Seoul, Korea; and Friedman School of Nutrition Science and Policy (S.-W.C.), Tufts University, Boston, Massachusetts 02111.
authors.forename: Paolo
authors.initials: P
authors.lastname: Cavarzere
authors.affiliation: Departments of Medicine (F.P., S.F., F.M., C.Z., S.U., O.O.) Life and Reproduction Sciences (F.A., A.Ga., P.C.), Pathology and Diagnostics (G.S.), and Biotechnology (A.Gi., G.S.), University of Verona, 37134 Verona, Italy; Chaum Life Center (S.-W.C.), CHA University, 135-081 Seoul, Korea; and Friedman School of Nutrition Science and Policy (S.-W.C.), Tufts University, Boston, Massachusetts 02111.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Salvagno
authors.affiliation: Departments of Medicine (F.P., S.F., F.M., C.Z., S.U., O.O.) Life and Reproduction Sciences (F.A., A.Ga., P.C.), Pathology and Diagnostics (G.S.), and Biotechnology (A.Gi., G.S.), University of Verona, 37134 Verona, Italy; Chaum Life Center (S.-W.C.), CHA University, 135-081 Seoul, Korea; and Friedman School of Nutrition Science and Policy (S.-W.C.), Tufts University, Boston, Massachusetts 02111.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Giorgetti
authors.affiliation: Departments of Medicine (F.P., S.F., F.M., C.Z., S.U., O.O.) Life and Reproduction Sciences (F.A., A.Ga., P.C.), Pathology and Diagnostics (G.S.), and Biotechnology (A.Gi., G.S.), University of Verona, 37134 Verona, Italy; Chaum Life Center (S.-W.C.), CHA University, 135-081 Seoul, Korea; and Friedman School of Nutrition Science and Policy (S.-W.C.), Tufts University, Boston, Massachusetts 02111.
authors.forename: Giulia
authors.initials: G
authors.lastname: Speziali
authors.affiliation: Departments of Medicine (F.P., S.F., F.M., C.Z., S.U., O.O.) Life and Reproduction Sciences (F.A., A.Ga., P.C.), Pathology and Diagnostics (G.S.), and Biotechnology (A.Gi., G.S.), University of Verona, 37134 Verona, Italy; Chaum Life Center (S.-W.C.), CHA University, 135-081 Seoul, Korea; and Friedman School of Nutrition Science and Policy (S.-W.C.), Tufts University, Boston, Massachusetts 02111.
authors.forename: Sang-Woon
authors.initials: SW
authors.lastname: Choi
authors.affiliation: Departments of Medicine (F.P., S.F., F.M., C.Z., S.U., O.O.) Life and Reproduction Sciences (F.A., A.Ga., P.C.), Pathology and Diagnostics (G.S.), and Biotechnology (A.Gi., G.S.), University of Verona, 37134 Verona, Italy; Chaum Life Center (S.-W.C.), CHA University, 135-081 Seoul, Korea; and Friedman School of Nutrition Science and Policy (S.-W.C.), Tufts University, Boston, Massachusetts 02111.
authors.forename: Oliviero
authors.initials: O
authors.lastname: Olivieri
mesh_terms: D043209:11-beta-Hydroxysteroid Dehydrogenase Type 2 / Q000235:genetics*; D000293:Adolescent; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D043204:Mineralocorticoid Excess Syndrome, Apparent / Q000235:genetics*; D009154:Mutation; D010375:Pedigree; D010641:Phenotype; D011401:Promoter Regions, Genetic
chemical_list: D043209:11-beta-Hydroxysteroid Dehydrogenase Type 2; C468387:HSD11B2 protein, human