The proposed studies are aimed at elucidating the molecular genetic bases of two inherited forms of low-renin childhood hypertension: apparent mineralocorticoid excess (AME; probably an autosomal recessive disorder) and dexamethasone-suppressible hyperaldosteronism (DSH; and autosomal dominant disorder). Patients with these disorders will be identified by detailed endocrinologic studies, and DNA samples from patients and family members will be obtained.
In Specific Aim I, mutations in the gene encoding corticosteroid 11beta-dehydrogenase (11-DH) will be studied as a cause of AME. Sequence analysis of genomic clones encoding human 11-DH will be completed. Possible major deletions or rearrangements of the 11-DH genes in patients with AME will be detected by blot hybridization analysis of DNA samples. Small mutations in the 11-DH genes of patients will be identified by sequence analysis of cloned mutant genomic genes or of segments amplified by the polymerase chain reaction. The normal human 11- DH enzyme will be expressed from cDNA in cell culture, either by transfection of a plasmid containing a strong promoter or by infection of recombinant vaccinia virus. To determine the effects of each mutation detected in AME patients using in vitro mutagenesis and one of the above expression systems. If particular mutations are suspected to affected expression, normal and mutant promoter activities will be analyzed by ligating the promoters to an indicator gene and transfecting into a cell line expressing intrinsic 11-DH activity.
In Specific Aim II, mutations in the steroid 11-hydroxylase (P450cll) gene (CYP11B1 and CYP11B2) will be studied as a possible cause of DSH. A linkage analysis of DSH will be carried out using P450cll cDNA and DNA samples from patients with DSH and their families. If CYP11B polymorphisms are not sufficiently informative the linkage analysis will be extended to additional polymorphic probes on chromosome 8q that flank CYP11B1 and B2. If the linkage analysis is consistent with the hypothesis that DSH is caused by a mutation in or near either of the CYP11B genes, mutant CYP11B genes from patients with DSH will be isolated and sequenced to identify each mutation. If missense mutations are identified, normal and mutant enzymes will be expressed in cell culture to determine the effect of each mutation on regulation of 18-oxidase activity.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
1R01DK042169-01A1
Application #
3243218
Study Section
Endocrinology Study Section (END)
Project Start
1990-08-15
Project End
1993-06-30
Budget Start
1990-08-15
Budget End
1991-06-30
Support Year
1
Fiscal Year
1990
Total Cost
Indirect Cost
Name
Weill Medical College of Cornell University
Department
Type
Schools of Medicine
DUNS #
201373169
City
New York
State
NY
Country
United States
Zip Code
10065
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Mune, Tomoatsu; Suwa, Tetsuya; Morita, Hiroyuki et al. (2013) Longer HSD11B2 CA-repeat in impaired glucose tolerance and type 2 diabetes. Endocr J 60:671-8
Mune, Tomoatsu; Morita, Hiroyuki; Suzuki, Takashi et al. (2003) Role of local 11 beta-hydroxysteroid dehydrogenase type 2 expression in determining the phenotype of adrenal adenomas. J Clin Endocrinol Metab 88:864-70
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Agarwal, A K (2001) Transcriptional influence of two poly purine-pyrimidine tracts located in the HSD11B2 (11beta-hydroxysteroid dehydrogenase type 2) gene. Endocr Res 27:1-9
White, P C; Agarwal, A K; Nunez, B S et al. (2000) Genotype-phenotype correlations of mutations and polymorphisms in HSD11B2, the gene encoding the kidney isozyme of 11beta-hydroxysteroid dehydrogenase. Endocr Res 26:771-80
Agarwal, A K; White, P C (2000) Structure of the VPATPD gene encoding subunit D of the human vacuolar proton ATPase. Biochem Biophys Res Commun 279:543-7
Agarwal, A K; Giacchetti, G; Lavery, G et al. (2000) CA-Repeat polymorphism in intron 1 of HSD11B2 : effects on gene expression and salt sensitivity. Hypertension 36:187-94
Agarwal, A K (2000) Expression of HSD11K (NAD+ dependent 11beta-hydroxysteroid dehydrogenase) promoter constructs in renal cell lines. Endocr Res 26:289-302

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