Fabry disease female proband with clinical manifestations similar to hypertrophic cardiomyopathy.
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Fabry's disease is an X-linked inborn error of glycosphingolipid catabolism, resulting from a deficiency in alpha-galactosidase A (alpha-Gal A). A 56-year-old Japanese woman was at first suspected of having hypertrophic cardiomyopathy. The patient and her son had alpha-Gal A activity in leukocytes that was remarkably below the limit of controls. DNA analysis of the alpha-Gal A gene revealed a novel missense mutation at codon 19 in exon 1, resulting in leucine-to-proline substitution. As a result she was confirmed as a classic Fabry heterozygote. Recent advances in enzyme replacement therapy can reverse the storage of glycosphingolipids in Fabry's disease. Thus, in patients with cardiac hypertrophy, it is important to differentiate Fabry's disease from other causes of hypertrophy. Therefore, it is necessary to measure alpha-Gal A activity in all suspected cases and to analyze genetic abnormalities in heterozygotes. (+info)
Immunoquantification of alpha-galactosidase: evaluation for the diagnosis of Fabry disease.
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BACKGROUND: Fabry disease is an X-linked inborn error of glycosphingolipid catabolism resulting from a deficiency of the lysosomal exoglycohydrolase, alpha-galactosidase. Enzyme replacement therapy is currently available for Fabry disease, but early diagnosis before the onset of irreversible pathology will be mandatory for successful treatment. Presymptomatic detection would be possible through the use of a newborn-screening program. We report on the use of sensitive assays for the measurement of alpha-galactosidase protein and activity and for the protein saposin C, which are diagnostic markers for Fabry disease. METHODS: Two sensitive immunoassays for the measurement of alpha-galactosidase activity and protein were used to determine the concentrations of alpha-galactosidase in dried filter-paper blood spots and plasma samples from control patients and patients with a lysosomal storage disorder (LSD). RESULTS: Fabry hemizygous individuals were clearly identified from control populations by decreases in both alpha-galactosidase activity and protein. Fabry heterozygotes generally fell between the hemizygotes and controls. Including the measurement of saposin C enabled differentiation between Fabry heterozygotes and controls. In blood spots, all Fabry individuals could be distinguished from control blood spots as well as from 16 other LSD patients. CONCLUSIONS: The determination of alpha-galactosidase activity or protein in dried filter-paper blood spots could be used for the diagnosis of Fabry patients. With further validation, these assays could be used for the identification of Fabry patients in newborn-screening programs and may also be suitable for screening high-risk populations. (+info)
Enzyme replacement therapy in severe Fabry disease with renal failure: a 1-year follow-up.
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We present here the course of clinical response of a 53-year-old haemodialysed Fabry patient who received recombinant human alpha-galactosidase A at a dose of 1 mg/kg every other week over a period of 1 year. The therapy was well tolerated by the patient, who revealed an impressive favourable cutaneous, gastrointestinal, neurological and psychiatric response and a dramatic improvement in his quality of life, but no improvement in cardiac and renal function. (+info)
Transgenic mouse expressing human mutant alpha-galactosidase A in an endogenous enzyme deficient background: a biochemical animal model for studying active-site specific chaperone therapy for Fabry disease.
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Fabry disease is an inborn error of glycosphingolipid metabolism caused by the deficiency of lysosomal alpha-galactosidase A (alpha-Gal A). We have established transgenic mice that exclusively express human mutant alpha-Gal A (R301Q) in an alpha-Gal A knock-out background (TgM/KO mice). This serves as a biochemical model to study and evaluate active-site specific chaperone (ASSC) therapy for Fabry disease, which is specific for those missense mutations that cause misfolding of alpha-Gal A. The alpha-Gal A activities in the heart, kidney, spleen, and liver of homozygous TgM/KO mice were 52.6, 9.9, 29.6 and 44.4 unit/mg protein, respectively, corresponding to 16.4-, 0.8-, 0.6- and 1.4-fold of the endogenous enzyme activities in the same tissues of non-transgenic mice with a similar genetic background. Oral administration of 1-deoxygalactonojirimycin (DGJ), a competitive inhibitor of alpha-Gal A and an effective ASSC for Fabry disease, at 0.05 mM in the drinking water of the mice for 2 weeks resulted in 13.8-, 3.3-, 3.9-, and 2.6-fold increases in enzyme activities in the heart, kidney, spleen and liver, respectively. No accumulation of globotriaosylceramide, a natural substrate of alpha-Gal A, could be detected in the heart of TgM/KO mice after DGJ treatment, indicating that degradation of the glycolipid in the heart was not inhibited by DGJ at that dosage. The alpha-Gal A activity in homozygous or heterozygous fibroblasts established from TgM/KO mice (TMK cells) was approximately 39 and 20 unit/mg protein, respectively. These TgM/KO mice and TMK cells are useful tools for studying the mechanism of ASSC therapy, and for screening ASSCs for Fabry disease. (+info)
Bioluminescent imaging of a marking transgene and correction of Fabry mice by neonatal injection of recombinant lentiviral vectors.
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Successful therapy for many inherited disorders could be improved if the intervention were initiated early. This is especially true for lysosomal storage disorders. Earlier intervention may allow metabolic correction to occur before lipid buildup has irreversible consequences and/or before the immune system mounts limiting responses. We have been developing gene therapy to treat lysosomal storage disorders, especially Fabry disease. We describe studies directed toward metabolic correction in neonatal animals mediated by recombinant lentiviral vectors. To develop this method, we first injected a marking lentiviral vector that engineers expression of luciferase into the temporal vein of recipient neonatal animals. The use of a cooled charged-coupled device camera allowed us to track transgene expression over time in live animals. We observed intense luciferase expression in many tissues, including the brain, that did not diminish over 24 weeks. Next, we injected neonatal Fabry mice a single time with a therapeutic lentiviral vector engineered to express human alpha-galactosidase A. The injection procedure was well tolerated. We observed increased plasma levels of alpha-galactosidase A activity starting at our first plasma collection point (4 weeks). Levels of alpha-galactosidase A activity were found to be significantly elevated in many tissues even after 28 weeks. No immune response was observed against the corrective transgene product. Increased levels of enzyme activity also led to significant reduction of globotriaosylceramide in the liver, spleen, and heart. This approach provides a method to treat lysosomal storage disorders and other disorders before destructive manifestations occur. (+info)
Intracellular accumulation of phospholipids may be a consequence of inherited or acquired metabolic disorders. In Fabry disease, deficiency of alpha-galactosidase A results in storage of globotriasylceramide in numerous cells including endothelium, striated muscle (skeletal, cardiac), smooth muscle, and renal epithelium among others; the ultrastructural appearance of the inclusions is of whorled layers of alternating dense and pale material ('zebra bodies' or myeline figures). Chloroquine therapy may result in storage of biochemically and ultrastructurally similar inclusions in many of the same cells as Fabry disease and often results in similar clinical manifestations. We report a 56-year-old woman with rheumatoid arthritis treated with chloroquine, who developed muscle weakness and renal insufficiency; information regarding therapy was not emphasized at the time of renal biopsy, leading to initial erroneous interpretation of Fabry disease. Following muscle biopsy, genetic and enzyme evaluation, and additional studies on the kidney biopsy, a diagnosis of chloroquine toxicity was established. One year following cessation of chloroquine, renal and muscle dysfunction greatly improved. In chloroquine toxicity, inclusions in glomeruli are not only in visceral epithelial, endothelial and mesangial cells but are in infiltrating monocytes/macrophages, which are most commonly present in the mesangium. Curvilinear bodies, the ultrastructural features of chloroquine toxicity in striated muscle, are not present in renal cells. This report documents differences in appearance, cells affected and morphological differential diagnostic features to distinguish these two entities. (+info)
A synthetic chaperone corrects the trafficking defect and disease phenotype in a protein misfolding disorder.
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Mutations in proteins that induce misfolding and proteasomal degradation are common causes of inherited diseases. Fabry disease is a lysosomal storage disorder caused by a deficiency of alpha-galactosidase A activity in lysosomes resulting in an accumulation of glycosphingolipid globotriosylceramide (Gb3). Some classical Fabry hemizygotes and all cardiac variants have residual alpha-galactosidase A activity, but the mutant enzymes are unstable. Such mutant enzymes appear to be misfolded, recognized by the ER protein quality control, and degraded before sorting into lysosomes. Hence, correction of the trafficking defect of mutant but catalytically active enzyme into lysosomes would be beneficial for treatment of the disease. Here we show that a nontoxic competitive inhibitor (1-deoxygalactonojirimycin) of alpha-galactosidase A functions as a chemical chaperone by releasing ER-retained mutant enzyme from BiP. The treatment with subinhibitory doses resulted in efficient, long-term lysosomal trafficking of the ER-retained mutant alpha-galactosidase A. Successful clearance of lysosomal Gb3 storage and a near-normal lysosomal phenotype was achieved in human Fabry fibroblasts harboring different types of mutations. Small molecule chemical chaperones will be therapeutically useful for various lysosomal storage disorders as well as for other genetic metabolic disorders caused by mutant but nonetheless catalytically active enzymes. (+info)
Alpha-galactosidase A deficiency accelerates atherosclerosis in mice with apolipoprotein E deficiency.
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BACKGROUND: Alpha-galactosidase A (Gla) deficiency leads to widespread tissue accumulation of neutral glycosphingolipids and is associated with premature vascular complications such as myocardial infarction and stroke. Glycosphingolipids have been shown to accumulate in human atherosclerotic lesions, although their role in atherogenesis is unclear. METHODS AND RESULTS: To determine whether Gla affects the progression of atherosclerosis, mice were generated with combined deficiencies of apolipoprotein E and Gla. At 45 weeks of age, Gla-deficient mice had developed more atherosclerosis than mice with normal Gla expression (25.1+/-14.0 versus 12.3+/-9.3 mm2 of total lesion area, P<0.02). This increase in atherosclerosis was associated with the presence of increased Gb3, enhanced inducible nitric oxide synthase expression, and increased nitrotyrosine staining. CONCLUSIONS: These findings suggest that deficiency of Gla leads to increased inducible nitric oxide synthase expression and accelerated atherosclerosis. (+info)