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Uitto J.,Jefferson Medical College | Jiang Q.,Jefferson Medical College | Varadi A.,Hungarian Academy of Sciences | Bercovitch L.G.,Brown University | Terry S.F.,PXE International
Expert Opinion on Orphan Drugs | Year: 2014

Introduction: Pseudoxanthoma elasticum (PXE), a multisystem orphan disease, clinically affects the skin, the eyes and the cardiovascular system with considerable morbidity and mortality. The clinical manifestations reflect the underlying pathology consisting of ectopic mineralization of peripheral connective tissues. Areas covered: The diagnostic criteria of PXE include characteristic clinical findings, together with histopathology of accumulation of pleiomorphic elastic structures in the dermis with progressive mineralization, and the presence of mutations in the ABCC6 gene. PXE-like cutaneous changes can also be encountered in other ectopic mineralization disorders, including generalized arterial calcification of infancy (GACI) caused by mutations in the ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) gene. In some cases, overlapping clinical features of PXE/GACI, associated with mutations either in ABCC6 or ENPP1, have been noted. PXE demonstrates considerable inter- and intrafamilial heterogeneity, and consequently, accurate diagnosis is required for appropriate classification with prognostic implications. There is no effective and specific treatment for the systemic manifestations of PXE, but effective therapies to counteract the ocular complications are in current clinical use. Expert opinion: A number of observations in the animal model, the Abcc6-/- , mouse, have indicated that the mineral composition of diet, particularly the magnesium content, can influence the severity of the mineralization phenotype. These observations suggest that appropriate dietary interventions, coupled with lifestyle modifications, including smoking cessation, might alleviate the symptoms and improve the quality of life of individuals affected with this, currently intractable, orphan disease. © 2014 Informa UK, Ltd. Source

Li Q.,Thomas Jefferson University | Sundberg J.P.,The Jackson Laboratory | Levine M.A.,Childrens Hospital of Philadelphia | Terry S.F.,PXE International | Uitto J.,Thomas Jefferson University
Cell Cycle | Year: 2015

Pseudoxanthoma elasticum (PXE) and generalized arterial calcification of infancy (GACI) are heritable ectopic mineralization disorders. Most cases of PXE and many cases of GACI harbor mutations in the ABCC6 gene. There is no effective treatment for these disorders. We explored the potential efficacy of bisphosphonates to prevent ectopic calcification caused by ABCC6 mutations by feeding Abcc6–/– mice with diet containing etidronate disodium (ETD) or alendronate sodium trihydrate (AST) in quantities corresponding to 1x, 5x, or 12x of the doses used to treat osteoporosis in humans. The mice were placed on diet at 4 weeks of age, and the degree of mineralization was assessed at 12 weeks by quantitation of the calcium deposits in the dermal sheath of vibrissae, a progressive biomarker of the mineralization, by computerized morphometry of histopathologic sections and by direct chemical assay of calcium. We found that ETD, but not AST, at the 12x dosage, significantly reduced mineralization, suggesting that selected bisphosphonates may be helpful for prevention of mineral deposits in PXE and GACI caused by mutations in the ABCC6 gene, when combined with careful monitoring of efficacy and potential side-effects. © 2015 Taylor & Francis Group, LLC. Source

Li Q.,Thomas Jefferson University | Guo H.,Thomas Jefferson University | Chou D.W.,Thomas Jefferson University | Harrington D.J.,HealthCare Partners | And 3 more authors.
American Journal of Pathology | Year: 2013

Pseudoxanthoma elasticum (PXE) is a multisystem ectopic mineralization disorder caused by mutations in the ABCC6 gene. Warfarin, a commonly used anticoagulant, is associated with increased mineralization of the arterial blood vessels and cardiac valves. We hypothesized that warfarin may accelerate ectopic tissue mineralization in PXE, with clinical consequences. To test this hypothesis, we developed a model in which Abcc6-/- mice, which recapitulate features of PXE, were fed a diet supplemented with warfarin and vitamin K1. Warfarin action was confirmed by significantly increased serum levels of oxidized vitamin K. For mice placed on a warfarin-containing diet, quantitative chemical and morphometric analyses revealed massive accumulation of mineral deposits in a number of tissues. Mice fed a warfarin-containing diet were also shown to have abundant uncarboxylated form of matrix Gla protein, which allowed progressive tissue mineralization to ensue. To explore the clinical relevance of these findings, 1747 patients with PXE from the approximately 4000 patients in the PXE International database were surveyed about the use of warfarin. Of the 539 respondents, 2.6% reported past or present use of warfarin. Based on the prevalence of PXE (approximately 1:50,000), thousands of patients with PXE worldwide may be at risk for worsening of PXE as a result of warfarin therapy. Copyright © 2013 American Society for Investigative Pathology. Source

Baxter K.,Genetic Alliance | Baxter K.,Booz Allen Hamilton | Horn E.,Genetic Alliance | Gal-Edd N.,Genetic Alliance | And 4 more authors.
Science Translational Medicine | Year: 2013

A new map is presented for creating an open, collaborative, and coordinated system for drug development. Source

Pxe International | Date: 2002-03-13

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