Section on Ophthalmic Molecular Genetics
This section has been involved in a number of different to study inherited visual diseases affecting the lens and the retina.
One approach to understanding inherited visual diseases uses principles of positional cloning to identify genes important in human inherited diseases. Such diseases currently undergoing linkage analysis, gene isolation, or characterization of mutations include Usher syndrome, retinitis pigmentosa, inherited cataracts, Bietti crystalline dystrophy, and a number of corneal dystrophies.
A second approach is to attempt to establish associations between sequence changes in candidate genes and specific phenotypes. This type of study is most applicable to prevalent diseases with a complex inheritance pattern, and is currently being used for age related cataracts.
Once a candidate gene has been identified and confirmed, the biochemical and pathophysiological implications of identified mutations are explored both in vitro through recombinant expression of native and mutant proteins and in vivo through transgenic expression of pathological proteins. To date, most of these studies have involved mutations in the lens crystallins. Lens crystallins make up more than 90 percent of the soluble protein of lens and are heavily modified in most cataracts. The effects that specific modifications of and crystallin structure produce on crystallin function such as stability, resistance to damage by ultraviolet light, and formation of macromolecular aggregates are being studied. Regions of the beta-crystallin molecule of special interest include the amino and carboxy terminal arms, the connecting peptide and the Greek key motifs of the core domains. In addition, the interactions of acidic and basic-crystallins are being studied.
|J. Fielding Hejtmancik, M.D., Ph.D.||Section Chieffirstname.lastname@example.org||(301) 496-8300|
|Xiaodong Jiao||Biologistemail@example.com||(301) 435-2586|
|Anren Li||Biologist||Anren@intra.nei.nih.gov||(301) 496-8300|
|Yuri Sergeev, Ph.D.||Staff Scientistfirstname.lastname@example.org||(301) 496-8300|
Scott MH, Hejtmancik JF, Wozencraft LA, Reuter LM, Parks MM, and Kaiser-Kupfer MI: Autosomal dominant congenital cataract: Interocular phenotypic heterogeneity. Ophthalmology. 101:866-871, 1994.
Ayyagari R, Smith RJH, Polymeropolous M, Daiger S, Pelias MZ, Wozencraft L, Kaiser-Kupfer M, and Hejtmancik JF: Localization of the Usher syndrome type 1 gene in the French Acadian population of Louisiana to chromosome 11p14-15.1 by linkage and haplotype analysis. Indian Journal of Human Genetics 1:93-103, 1996.
Alberti G, Oguni M, Podgor M, Sperduto RD, Tomarev S, Grassi C, Williams S, Kaiser-Kupfer M, Maraini G, Hejtmancik JF: Glutathione S-transferase M1 genotype and age-related cataracts. Lack of association in an Italian population. Invest Ophthalmol Vis Sci1996 May;37(6):1167-73
Ayyagari R, Nestorowicz A, Li Y, Chandrasekharappa S, Chinault C, van Tuinen P, Smith RJ, Hejtmancik JF, Permutt MA: Construction of a YAC contig encompassing the Usher syndrome type 1C and familial hyperinsulinism loci on chromosome 11p14-15.1. Genome Res 1996 Jun;6(6):504-14
Hejtmancik JF, Wingfield PT, Chambers C, Russell P, Chen HC, Sergeev YV, Hope JN: Association properties of betaB2- and betaA3-crystallin: ability to form dimers. Protein Eng 1997 Nov;10(11):1347-52
Hejtmancik JF: The genetics of cataract: our vision becomes clearer. Am J Hum Genet 1998 Mar;62(3):520-5.
Sergeev YV, David LL, Chen HC, Hope JN, Hejtmancik JF: Local microdomain structure in the terminal extensions of betaA3- and betaB2-crystallins. Mol Vis1998 Jun 18;4:9
Lee J, Jiao X, Hejtmancik JF, Kaiser-Kupfer M, Chader GJ: Identification, isolation, and characterization of a 32-kDa fatty acid-binding protein missing from lymphocytes in humans with Bietti crystalline dystrophy (BCD). Mol Genet Metab1998 Oct;65(2):143-54
Kannabiran C, Rogan PK, Olmos L, Basti S, Rao GN, Kaiser-Kupfer M, Hejtmancik JF: Autosomal dominant zonular cataract with sutural opacities is associated with a splice mutation in the betaA3/A1-crystallin gene. Mol Vis1998 Oct 23;4:21