GLA Gene Mutation in Hypertrophic Cardiomyopathy with a New Variant Description: Is it Fabry's Disease? / Mutação do Gene GLA na Cardiomiopatia Hipertrófica com Descrição de Nova Variante: É Doença de Fabry?

Abstract Background: Fabry disease (FD) is an X-linked lysosomal storage disorder caused by mutations in the alpha galactosidase A gene (GLA) that lead to the enzymatic deficiency of alpha galactosidase (α-Gal A), resulting in the accumulation of globotriaosylceramide (Gb3) and globotriaosylsphingosine (lyso-Gb3), causing multiple organ dysfunctions. Objective: To perform GLA gene screening in a group of patients with echocardiographic diagnosis of hypertrophic cardiomyopathy (HCM). Methods: a cross-sectional study was conducted with HCM patients from a university hospital. Patients with coronary artery disease and valvulopathies were excluded. Mutation analysis of the GLA gene was performed. In male subjects, the analysis was performed after evidence of low α-Gal A activity. Results: 60 patients with echocardiographic diagnosis of HCM were included. Age ranged from 12 to 85 years and 60% were women. Mean myocardial fibrosis percentage on MRI was 10.7 ± 13.1% and mean ventricular thickness was18.7 ± 6.7 mm. Four patients had the following GLA gene mutations: c.967C>A (p.Pro323Thr), not yet described in the literature; c.937G>T (p.Asp313Tyr); and c.352C>T (p.Arg118Cys). All patients had normal levels of lyso-Gb3 and non-ischemic myocardial fibrosis on magnetic resonance imaging; one patient had proteinuria and one patient had ventricular tachycardia. Conclusion: in this study, the frequency of mutation in the GLA gene in patients with HCM was 6.7%. A novel mutation in exon 6 of the GLA gene, c.967C>A (p.Pro323Thr), was identified. Patients with HCM may have GLA mutations and FD should be ruled out. Plasma (lyso-Gb3) levels do not seem to be sufficient to attain a diagnosis and organ biopsy should be considered.

Resumo Fundamento: A doença de Fabry (DF) é uma doença de armazenamento lisossômico ligada ao cromossomo X, devido a mutações no gene da alfa galactosidase A (GLA), levando a deficiência enzimática de alfa-galactosidase (α-Gal A) e acúmulo de globotriaosilceramida (Gb3) e globotriaosilsulfingosina (liso-Gb3), causando disfunção de múltiplos órgãos. Objetivo: realizar a triagem do gene GLA em um grupo de pacientes com diagnóstico ecocardiográfico de cardiomiopatia hipertrófica (CMH). Métodos: estudo transversal realizado com pacientes com CMH em um hospital universitário. Pacientes com doença arterial coronariana e valvopatias foram excluídos. Foi realizada análise de mutação do gene GLA. Em indivíduos do sexo masculino, a análise foi realizada após evidência de baixa atividade de α-Gal A. Resultados: Foram incluídos 60 pacientes com diagnostico ecocardiográfico de CMH. A idade variou de 12 a 85 anos e 60% eram mulheres. O percentual médio de fibrose miocárdica na RM foi 10,7 ± 13,1% e a espessura ventricular média foi 18,7 ± 6,7 mm. Quatro pacientes tinham as seguintes mutações do GLA: c.967C>A (p.Pro323Thr), ainda não descrita na literatura; c.937G>T (p.Asp313Tyr); e c.352C>T (p.Arg118Cys). Todos os pacientes apresentavam níveis normais de liso-Gb3 e fibrose miocárdica não isquêmica na ressonância magnética; um paciente apresentou proteinúria; um paciente apresentou taquicardia ventricular. Conclusão: Neste estudo, a frequência de mutação no gene GLA em pacientes com CMH foi 6,7%. Uma nova mutação no exon 6 do gene GLA, c.967C>A (p.Pro323Thr), foi identificada. Pacientes com CMH podem ter mutações do GLA e a DF deve ser excluída. Os níveis plasmáticos de (liso-Gb3) não parecem ser suficientes para fazer um diagnóstico e biópsia de órgãos deve ser considerada.

Case report: is low α-Gal enzyme activity sufficient to establish the diagnosis of Fabry disease? / Relato de caso: a diminuição da enzimaα-Gal l é suficiente para estabelecer o diagnóstico?

Abstract Fabry disease is an X-linked lysosomal storage disease due to alpha-galactosidase A (α-Gal A) deficient activity which leads to the accumulation of glucoesphingolipids, such as globotriaosilceramide. There are over 700 known mutations of the enzyme gene, and most of them cause Fabry Disease. This case report describes a hemodialysis patient with a rare and controversial GLA gene mutation, the D313Y. The medecial investigation confirmed that D313Y is an alpha-galactosidase A sequence variant that causes pseudo deficient enzyme activity in plasma but not Fabry disease. Thus, clinical symptoms that prompted Fabry disease investigation could not be attributable to Fabry disease and therefore enzyme replacement therapy was not indicated.

Resumo Doença de Fabry (DF) é uma doença de depósito lisossômico ligada ao cromossomo X, causada pela deficiência da enzima alfa-galactosidase A (α-Gal A) que leva ao acúmulo de glicoesfingolipídeos, principalmente globotriaosilceramide. Existem mais de 700 mutações conhecidas do gene da enzima, a maioria delas são causadoras de DF. Este relato de caso descreve sobre um paciente em hemodiálise com uma mutação do gene GLA rara e controversa, a D313Y. A investigação médica confirmou que D313Y é uma variante que leva à pseudodeficiência plasmática da enzima, mas não ocasiona DF. Assim, os sintomas clínicos que induziram a investigação da doença não devem ser atribuídos à DF e, portanto, não foi indicada a terapia de reposição enzimática.

Screening for Fabry Disease in Left Ventricular Hypertrophy: Documentation of a Novel Mutation / Rastreio de Doença de Fabry na Hipertrofia Ventricular Esquerda: Documentação de uma Nova Mutação

AbstractBackground:Fabry disease is a lysosomal storage disease caused by enzyme α-galactosidase A deficiency as a result of mutations in the GLA gene. Cardiac involvement is characterized by progressive left ventricular hypertrophy.Objective:To estimate the prevalence of Fabry disease in a population with left ventricular hypertrophy.Methods:The patients were assessed for the presence of left ventricular hypertrophy defined as a left ventricular mass index ≥ 96 g/m2 for women or ≥ 116 g/m2 for men. Severe aortic stenosis and arterial hypertension with mild left ventricular hypertrophy were exclusion criteria. All patients included were assessed for enzyme α-galactosidase A activity using dry spot testing. Genetic study was performed whenever the enzyme activity was decreased.Results:A total of 47 patients with a mean left ventricular mass index of 141.1 g/m2 (± 28.5; 99.2 to 228.5 g/m2] were included. Most of the patients were females (51.1%). Nine (19.1%) showed decreased α-galactosidase A activity, but only one positive genetic test − [GLA] c.785G>T; p.W262L (exon 5), a mutation not previously described in the literature. This clinical investigation was able to establish the association between the mutation and the clinical presentation.Conclusion:In a population of patients with left ventricular hypertrophy, we documented a Fabry disease prevalence of 2.1%. This novel case was defined in the sequence of a mutation of unknown meaning in the GLA gene with further pathogenicity study. Thus, this study permitted the definition of a novel causal mutation for Fabry disease - [GLA] c.785G>T; p.W262L (exon 5).

ResumoFundamento:A doença de Fabry é uma doença lisossomal de sobrecarga provocada pela deficiência da enzima α-galactosidase A como resultado de mutações no gene GLA. O envolvimento cardíaco carateriza-se por hipertrofia ventricular esquerda progressiva.Objetivo:Estimar a prevalência da doença de Fabry numa população com hipertrofia ventricular esquerda.Métodos:Os doentes foram avaliados para a presença de hipertrofia ventricular esquerda definida por massa do ventrículo esquerdo indexada como ≥ 96 g/m2 para mulheres ou ≥ 116 g/m2 para homens. Estenose aórtica severa e hipertensão arterial, com hipertrofia ventricular esquerda discreta, foram critério de exclusão. Todos os doentes incluídos foram avaliados para a atividade da enzima α-galactosidase A com testes de gota seca. No caso de atividade enzimática diminuída, realizava-se estudo genético.Resultados:Foram incluídos 47 doentes com uma média de massa indexada de 141,1 g/m2 (± 28,5; 99,2 a 228,5 g/m2]. A maioria (51,1%) dos doentes era do sexo feminino. Nove deles (19,1%) tinham diminuição da atividade da α-galactosidase A, mas apenas um teste genético foi positivo − [GLA] c.785G>T; p.W262L (éxon 5), uma mutação não descrita na literatura. O trabalho de investigação clínica permitiu estabelecer uma associação entre a mutação e a apresentação clínica.Conclusão:Em uma população de doentes com hipertrofia ventricular esquerda, documentamos uma prevalência de doença de Fabry de 2,1%. O novo caso foi definido na sequência de uma mutação de significado indeterminado no gene GLA com posterior estudo de patogenicidade. Este estudo permitiu, assim, definir uma nova mutação causal para doença de Fabry - [GLA] c.785G>T; p.W262L (éxon 5).

Fabry disease previously diagnosed as Henoch-Schonlein purpura

No abstract available.

Doença de Anderson-Faby: manifestações cardíacas: [revisão] / Anderson Fabry's disease: cardiac manifestations: [review]

A doença de Anderson-Fabry é uma desordem genética ligada ao cromossomo X, causada por deficiência parcial ou completa de uma enzima lisossomal, α-galactosidase A, resultando em deposição de glicoesfingolipídios e levando à morte prematura, principalmente por complicações renais, cardíacas e cerebrovasculares. O envolvimento cardíaco é, geralmente, parte de um acometimento sistêmico presente na quarta década de vida. Entretanto, uma variante da doença com acometimento cardíaco predominante tem sido reconhecida. Hipertrofia concêntrica do ventrículo esquerdo é um achado comum e essa doença deve ser suspeitada em pacientes com hipertrofia inexplicada do ventrículo esquerdo.

A Case of Fabry's Disease with Congenital Agammaglobulinemia

Fabry's disease is an X-linked lysosomal storage disorder caused by abnormalities in the alpha-galactosidase A (GLA) gene, which leads to a GLA deficiency and to the intracellular deposition of globotriaosylceramide (Gb3) within vascular endothelium and other tissues. It manifests as progressive multiple organ dysfunctions caused by the deposition of Gb3. On the other hand, congenital agammaglobulinemia is usually caused by mutations in Bruton's tyrosine kinase (Btk) gene with X-linked dominence, suppresses B cell maturation, and causes recurrent pyogenic infections. In former reports, the distance between the loci in the Xq22 region of the human X chromosome was found to be about 69 kilobases. A 23-yr-old man diagnosed with congenital agammaglobulinemia at age 5, showed typical clinical and laboratory and histopathological findings of Fabry's disease. The genetic basis of this combination of the two syndromes was studied in this patient. Here, we report a case of Fabry's disease with congenital agammaglobulinemia.

Evaluación de pacientes con enfermedad de Fabry en la Argentina / Evaluation of patients with Fabry disease in Argentina

La enfermedad de Fabry es un desorden lisosomal de transmisión ligada al cromosoma X debida al déficit de la enzima alfa galactosidasa A, con acumulación multisistémica de globotriaosilceramida y compromiso neurológico, gastrointestinal, cardíaco, renal, dermatológico y oftalmológico. Estudios recientes indican que las mujeres heterocigotas desarrollan síntomas similares a los de los varones, pero no existen en nuestro país datos comparativos respecto de la frecuencia relativa de manifestaciones clínicas, edad de inicio y gravedad entre hombres y mujeres con enfermedad de Fabry. Identificamos 59 pacientes adultos sintomáticos con enfermedad de Fabry: 32 varones (edad media: 34.8 años) y 27 mujeres (edad media: 46.6 años). El diagnóstico se hizo por estudios enzimáticos en los hombres y genéticos en las mujeres. Se evaluó la frecuencia y la gravedad de las manifestaciones de la enfermedad. Las manifestaciones más frecuentes fueron acroparestesias, angioqueratomas, hipohidrosis y córnea verticilada; las tres primeras fueron estadísticamente más frecuentes en hombres, en los cuales la gravedad de estos síntomas fue significativamente mayor. Proteinuria e hipertrofia ventricular izquierda fueron hallazgos frecuentes tanto en hombres como en mujeres. Hubo una latencia prolongada entre la edad del inicio y la del diagnóstico de 14 años para varones y 30 para mujeres. La enfermedad de Fabry es una enfermedad subdiagnosticada y potencialmente letal que afecta a ambos sexos. La existencia de reemplazo enzimático obliga a identificar precozmente los síntomas y signos sugestivos de la enfermedad para realizar un diagnóstico y tratamiento precoces.

Fabry disease is an X- linked lysosomal disorder due to deficient activity of the enzyme alpha galactosidase A which leads to multisystemic storage of globotriaosylceramide with neurologic, gastrointestinal, cardiac, renal, skin and ophtalmological involvement. Recent studies indicate that heterozygous females develop symptoms similar to the males, but comparative information regarding the relative frequency of clinical manifestations, age of onset and severity of the disorder between males and females with Fabry disease is not available in Argentina. We identified 59 symptomatic adult patients with Fabry disease: 32 males (mean age 34.8 years) and 27 females (mean age 46.6 years). Diagnosis was made by enzymatic analysis in males and by genetic studies in females. We compared the frequency and severity of the clinical manifestations in females and males with this disease. The most frequent manifestations were: acroparesthesias, angiokeratomas, hypohydrosis (all them were significantly more frequent in males than in females, as well as the severity of symptoms), and cornea verticillata. Proteinuria and ventricular hypertrophy were frequent findings both in males and females. There was a delayed latency between age at onset and age at diagnosis in our group: 14 years for men and 30 years for females. Fabry disease is an underdiagnosed and potentially fatal disorder that affects both sexes. The availability of enzyme replacement therapy should stimulate the identification of signs and symptoms suggestive of this disorder, to allow earlier diagnosis and treatment.

Serum Globotriaosylceramide Assay as a Screening Test for Fabry Disease in Patients with ESRD on Maintenance Dialysis in Korea

BACKGROUND/AIMS: Fabry disease is an X-linked recessive and progressive disease caused by alpha-galactosidase A (alpha-GaL A) deficiency. We sought to assess the prevalence of unrecognized Fabry disease in dialysis-dependent patients and the efficacy of serum globotriaosylceramide (GL3) screening. METHODS: A total of 480 patients of 1,230 patients among 17 clinics were enrolled. Serum GL3 levels were measured by tandem mass spectrometry. Additionally, we studied the association between increased GL3 levels and cardiovascular disease, cerebrovascular disease, or left ventricular hypertrophy. RESULTS: Twenty-nine patients had elevated serum GL3 levels. The alpha-GaL A activity was determined for the 26 patients with high GL3 levels. The mean alpha-GaL A activity was 64.6 nmol/hr/mg (reference range, 45 to 85), and no patient was identified with decreased alpha-GaL A activity. Among the group with high GL3 levels, 15 women had a alpha-GaL A genetics analysis. No point mutations were discovered among the women with high GL3 levels. No correlation was observed between serum GL3 levels and alpha-GaL A activity; the Pearson correlation coefficient was 0.01352 (p = 0.9478). No significant correlation was observed between increased GL3 levels and the frequency of cardiovascular disease or cerebrovascular disease. CONCLUSIONS: Fabry disease is very rare disease in patients with end-stage renal disease. Serum GL3 measurements as a screening method for Fabry disease showed a high false-positive rate. Thus, serum GL3 levels determined by tandem mass spectrometry may not be useful as a screening method for Fabry disease in patients with end stage renal disease.

Effects of a chemical chaperone on genetic mutations in alpha-galactosidase A in Korean patients with Fabry disease

Fabry disease is an X-linked inborn error of glycosphingolipid catabolism that results from mutations in the gene encoding the alpha-galactosidase A (GLA) enzyme. We have identified 15 distinct mutations in the GLA gene in 13 unrelated patients with classic Fabry disease and 2 unrelated patients with atypical Fabry disease. Two of the identified mutations were novel (i.e., the D231G missense mutation and the L268delfsX1 deletion mutation). This study evaluated the effects of the chemical chaperones 1-deoxygalactonojirimycin (DGJ) on the function of GLA in vitro, in cells containing missense mutations in the GLA gene. Nine missense and a nonsense mutations, including one novel mutation were cloned into mammalian expression vectors. After transient expression in COS-7 cells, GLA enzyme activity and protein expression were analyzed using fluorescence spectrophotometry and Western blot analysis, respectively. DGJ enhanced GLA enzyme activity in the M42V, I91T, R112C and F113L mutants. Interestingly, the I91T and F113L mutations are associated with the atypical form of Fabry disease. However, DGJ treatment did not have any significant effect on the GLA enzyme activity and protein expression of other mutants, including C142W, D231G, D266N, and S297F. Of note, GLA enzyme activity was not detected in the novel mutant (i.e., D231G), although protein expression was similar to the wild type. In the absence of DGJ, the E66Q mutant had wild-type levels of GLA protein expression and approximately 40% GLA activity, indicating that E66Q is either a mild mutation or a functional single nucleotide polymorphism (SNP). Thus, the results of this study suggest that the chemical chaperone DGJ enhances GLA enzyme activity and protein expression in milder mutations associated with the atypical form of Fabry disease.

Removal of Alpha-Gal Epitopes from Porcine Aortic Valve and Pericardium using Recombinant Human Alpha Galactosidase A

It has been reported that the immune response due to alpha-Gal epitopes is an important factor in tissue valve failure. The elimination of the interaction between the natural anti-Gal antibodies and alpha-gal epitopes on the xenografts is a prerequisite to the success of xenografts in humans. Previously, we reported that the green coffee bean alpha-galactosidase could remove all alpha-Gal epitopes from cell surface of porcine aortic valve and pericardial tissue, but it has limitations on cost effectiveness. In this study we wanted to know whether the recently produced recombinant human alpha-galactosidase A has the same effective enzymatic activity as green coffee bean alpha-galactosidase in removing alpha-Gal epitopes from the same tissues. After treating fresh porcine aortic valve and pericardial tissue with recombinant alpha-galactosidase A, each sample was stained with Griffonia simplicifolia type I isolectin B4 indirect immunoperoxidase avidin-biotin technique. We then examined whether the alpha-Gal epitopes were reduced or abolished in each consecutive concentration of recombinant alpha-galactosidase A by comparing the degree of the Griffonia simplicifolia isolectin B4 staining. As a result, the recombinant alpha-galactosidase A could remove cell surface alpha-Gals on porcine aortic valve and pericardial tissue as effectively as green coffee bean alpha-galactosidase.

Genomic analysis of Brazilian patients with Fabry disease

Fabry disease is an X-linked lysosomal disorder due to a-galactosidase A deficiency that causes storage of globotriaosylceramide. The gene coding for this lysosomal enzyme is located on the long arm of the X chromosome, in region Xq21.33-Xq22. Disease progression leads to vascular disease secondary to involvement of kidney, heart and the central nervous system. Detection of female carriers based solely on enzyme assays is often inconclusive. Therefore, mutation analysis is a valuable tool for diagnosis and genetic counseling. Many mutations of the a-galactosidase A gene have been reported with high genetic heterogeneity, being most mutations private found in only one family. The disease is panethnic, and estimates of incidence range from about 1 in 40,000 to 60,000 males. Our objective was to describe the analysis of 6 male and 7 female individuals belonging to 4 different Fabry disease families by automated sequencing of the seven exons of the a-galactosidase gene. Sequencing was performed using PCR fragments for each exon amplified from DNA extracted from peripheral blood. Three known mutations and one previously described in another Brazilian family were detected. Of 7 female relatives studied, 4 were carriers. Although the present study confirms the heterogeneity of mutations in Fabry disease, the finding of the same mutation previously detected in another Fabry family from our region raises the possibility of some founder effect, or genetic drift. Finally, the present study highlights the importance of molecular analysis for carrier detection and genetic counseling.

Reduction of non-digestible oligosaccharides in soymilk: application of engineered lactic acid bacteria that produce alpha-galactosidase

Human consumption of soy-derived products has been limited by the presence of non-digestible oligosaccharides (NDO), such as the alpha-galactooligosaccharides raffinose and stachyose. Most mammals, including man, lack pancreatic alpha-galactosidase (alpha-Gal), which is necessary for the hydrolysis of these sugars. However, such NDO can be fermented by gas-producing microorganisms present in the cecum and large intestine, which in turn can induce flatulence and other gastrointestinal disorders in sensitive individuals.The use of microorganisms expressing alpha-Gal is a promising solution to the elimination of NDO before they reach the large intestine. In the present study, lactic acid bacteria engineered to degrade NDO have been constructed and are being used as a tool to evaluate this solution. The alpha-Gal structural genes from Lactobacillus plantarum ATCC8014 (previously characterized in our laboratory) and from guar have been cloned and expressed in Lactococcus lactis. The gene products were directed to different bacterial compartments to optimize their possible applications. The alpha-Gal-producing strains are being evaluated for their efficiency in degrading raffinose and stachyose: i) in soymilk fermentation when used as starters and ii) in situ in the upper gastrointestinal tract when administered to animals orally, as probiotic preparations. The expected outcomes and possible complications of this project are discussed.