The genetics of antithrombin
Authors: Corral, Javier; Eugenia de la Morena-Barrio, Maria; Vicente, Vicente
Antithrombin is a key endogenous anticoagulant whose deficiency constitutes a strong risk factor for thrombosis. The study of antithrombin deficiency has generated excellent, and in some cases, surprising results that may be extrapolated to other thrombophilia and genetic disorders. Routine diagnosis of antithrombin deficiency is based on functional assays. Few specialized laboratories also perform genetic analysis, even though nowadays it is a simple, fast and cheap process that generates relevant information with clinical usefulness. Molecular analysis of SERPINC1, the gene encoding antithrombin, has been restricted so far to cases with confirmed or familial antithrombin deficiency. However, some pathogenic mutations are not detected by current functional methods and other gene defects may have functional consequences only observed under specific conditions. Thus, molecular analysis may be the best method to identify antithrombin deficiency. Up to 80% of patients with antithrombin deficiency have SERPINC1 gene defects, mostly (90% of the 315 gene defects described so far) point mutations or small deletions or insertions affecting the 7 exons or flanking regions. The description of new SERPINC1 gene defects may reveal new residues with functional or structural relevance and new mechanisms causing deficiency of this endogenous anticoagulant. Moreover, other genes and mechanisms may also be involved in antithrombin deficiency. Thus, disorders of N-glycosylation explain up to 5% of cases with antithrombin deficiency. However, there are still up to 10-15% of cases with antithrombin deficiency of unknown cause, whose study may reveal new genes and mechanisms involved in thrombosis.
Molecular networks in Dahl salt-sensitive hypertension based on transcriptome analysis of a panel of consomic rats
Authors: Liang, Mingyu; Lee, Norman H.; Wang, Hongying; Greene, Andrew S.; Kwitek, Anne E.; Kaldunski, Mary L.; Luu, Truong V.; Frank, Bryan C.; Bugenhagen, Scott; Jacob, Howard J.; Cowley, Allen W., Jr.
The Dahl salt-sensitive (SS) rat is a widely used model of human salt-sensitive hypertension and renal injury. We studied the molecular networks that underlie the complex disease phenotypes in the SS model, using a design that involved two consomic rat strains that were protected from salt-induced hypertension and one that was not protected. Substitution of Brown Norway (BN) chromosome 13 or 18, but not 20, into the SS genome was found to significantly attenuate salt-induced hypertension and albuminuria. Gene expression profiles were examined in the kidneys of SS and consomic SS-13(BN), SS-18(BN), and SS-20(BN) rats with a total of 240 cDNA microarrays. The substituted chromosome was overrepresented in genes differentially expressed between a consomic strain and SS rats on a 0.4% salt diet. F5, Serpinc1, Slc19a2, and genes represented by three other expressed sequence tags ( ESTs), which are located on chromosome 13, were found to be differentially expressed between SS-13(BN) and all other strains examined. Likewise, Acaa2, B4galt6, Colec12, Hsd17b4, and five other ESTs located on chromosome 18 exhibited expression patterns unique to SS-18(BN). On exposure to a 4% salt diet, there were 184 ESTs in the renal cortex and 346 in the renal medulla for which SS-13(BN) and SS-18(BN) shared one expression pattern, while SS and SS-20(BN) shared another, mirroring the phenotypic segregation among the four strains. Molecular networks that might contribute to the development of Dahl salt-sensitive hypertension and albuminuria were constructed with an approach that merged biological knowledge-driven analysis and data-driven Bayesian probabilistic analysis.