Unexpectedly High Prevalence of Low Alpha-Galactosidase A Enzyme Activity in Patients with Focal Segmental Glomerulosclerosis.

OBJECTIVES: Fabry disease (FD) is a rare disease associated with sphingolipid accumulation. Sphingolipids are components of plasma membranes that are important in podocyte function and accumulate in various glomerular diseases such as focal segmental glomerulosclerosis (FSGS). Both FD and FSGS can cause podocyte damage and are classified as podocytopathies. In this respect, FD and FSGS share the same pathophysiologic pathways. Previous screening studies have shown that a significant proportion of end-stage renal disease (ESRD) patients receiving hemodialysis (HD) have unsuspected FD, and the prevalence of low alpha-galactosidase A (αGLA) enzyme activity in these patients is higher than that in the normal population. We aimed to compare αGLA enzyme activity in patients with biopsy-proven FSGS and ESRD receiving HD. METHODS: The records of 232 patients [62 FSGS (F/M: 33/29); 170 HD (M/F: 93/79)] were evaluated retrospectively. The screening was performed based on the αGLA enzyme activity on a dried blood spot, with the confirmation of plasma LysoGb3 levels, and the known GLA mutations were tested in patients with low enzyme activities. The two groups were compared using these parameters. RESULTS: The mean level of αGLA enzyme activity was found to be lower in FSGS patients than in the HD group (2.88±1.2 µmol/L/h versus 3.79±1.9 µmol/L/h, p<0.001). There was no significant relationship between the two groups with regard to the plasma LysoGb3 levels (2.2±1.22 ng/ml versus 1.7±0.66 ng/ml, p: 0.4). In the analysis of GLA mutations, a D313Y mutation [C(937G>T) in exon p] was found in one patient from the FSGS group. CONCLUSIONS: We found that αGAL activity in patients with FSGS is lower than that in patients undergoing HD. The low enzyme activity in patients with FSGS may be explained by considering the similar pathogenesis of FSGS and FD, which may also lead to sphingolipid deposition and podocyte injury.

Unexpectedly High Prevalence of Low Alpha-Galactosidase A Enzyme Activity in Patients with Focal Segmental Glomerulosclerosis

OBJECTIVES: Fabry disease (FD) is a rare disease associated with sphingolipid accumulation. Sphingolipids are components of plasma membranes that are important in podocyte function and accumulate in various glomerular diseases such as focal segmental glomerulosclerosis (FSGS). Both FD and FSGS can cause podocyte damage and are classified as podocytopathies. In this respect, FD and FSGS share the same pathophysiologic pathways. Previous screening studies have shown that a significant proportion of end-stage renal disease (ESRD) patients receiving hemodialysis (HD) have unsuspected FD, and the prevalence of low alpha-galactosidase A (αGLA) enzyme activity in these patients is higher than that in the normal population. We aimed to compare αGLA enzyme activity in patients with biopsy-proven FSGS and ESRD receiving HD. METHODS: The records of 232 patients [62 FSGS (F/M: 33/29); 170 HD (M/F: 93/79)] were evaluated retrospectively. The screening was performed based on the αGLA enzyme activity on a dried blood spot, with the confirmation of plasma LysoGb3 levels, and the known GLA mutations were tested in patients with low enzyme activities. The two groups were compared using these parameters. RESULTS: The mean level of αGLA enzyme activity was found to be lower in FSGS patients than in the HD group (2.88±1.2 μmol/L/h versus 3.79±1.9 μmol/L/h, p<0.001). There was no significant relationship between the two groups with regard to the plasma LysoGb3 levels (2.2±1.22 ng/ml versus 1.7±0.66 ng/ml, p: 0.4). In the analysis of GLA mutations, a D313Y mutation [C(937G>T) in exon p] was found in one patient from the FSGS group. CONCLUSIONS: We found that αGAL activity in patients with FSGS is lower than that in patients undergoing HD. The low enzyme activity in patients with FSGS may be explained by considering the similar pathogenesis of FSGS and FD, which may also lead to sphingolipid deposition and podocyte injury.

Enfermedad de Fabry, a propósito de un caso interesante / Fabrys disease, a propos of an interesting case

La enfermedad de Fabry es una enfermedad por almacenamiento lisosómico hereditaria ligada al cromosoma X, y se deriva de mutaciones en el gen que codifica la enzima alfa-galactosidasa. Se presentó el caso de un paciente masculino de 33 años de edad, con antecedentes de hipertensión arterial, que presenta dolor en el pecho retroesternal, opresivo, quemante, se irradiaba a epigastrio, hombro izquierdo, mano izquierda, cuello y mandíbula, con una duración mayor de 30 minutos. Se sospechó de un infarto agudo de miocardio, pero al ser esta una patología poco frecuente en pacientes menores de 35 años, se decidió realizar una evaluación clínica, dermatológica, neurológica, oftalmológica, nefrológica y cardiológico, donde se constató síntomas típicos de la enfermedad de Fabry(AU)

Fabrys disease is a disease caused by hereditary lysosomic storage linked to the X chromosome, and derives from mutations on the gene codifying the alpha-galactosidase enzyme. It is presented the case of a male patient aged 33 years, with antecedents of arterial hypertension, referring oppressive, burning pain in the retrosternal chest, irradiating to epigastrium, left shoulder, left hand, neck and mandible, with more than 30 minutes last. An acute myocardial infarct was suspected, but being this pathology few frequent in patients aged less than 35 years, we decided a cardiologic, nephrological, ophthalmologic, neurologic, dermatologic and clinical evaluation, finding typical symptoms of the Fabrys disease(AU)

Screening for Fabry disease in left ventricular hypertrophy: documentation of a novel mutation.

BACKGROUND: 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).

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 peripheral blood immune cells release inflammatory cytokines: role of globotriaosylceramide.

Fabry disease is an X-linked lysosomal disorder (LD) due to deficiency of the enzyme α-galactosidase A (αGal), which leads to the accumulation of neutral glycosphingolipids, mainly globotriaosylceramide (Gb3). Several mechanisms contribute to the diverse physiopathological alterations observed in this disease, and it has been suggested that an underlying proinflammatory state could play a significant role. The aim of this study is to investigate the presence of a proinflammatory state in the different subsets of peripheral blood mononuclear cells (PBMC) and to understand the mechanisms that contribute to its onset and perpetuation. We have shown that cultured PBMC from Fabry patients present a higher proinflammatory cytokine expression and production. Moreover, we determined that among PBMC, dendritic cells and monocytes present a basal proinflammatory cytokine production profile, which is further exacerbated with an inflammatory stimulus. Finally we established that normal, monocyte-derived dendritic cells and macrophages display the same proinflammatory profile when cultured in the presence of Gb3 and an inhibitor of αGal. Furthermore, this effect can be abolished using a TLR4 blocking antibody, indicating that TLR4 is necessary in the process. In summary, our results demonstrate the presence of a proinflammatory state involving two key subsets of innate immunity, and provide direct evidence of Gb3 having a proinflammatory role, likely mediated by TLR4, a finding that could help in the understanding of the underlying causes of the inflammatory pathogenesis of Fabry disease.

Comparison between alpha-galactosidase A activity in blood samples collected on filter paper, leukocytes and plasma.

OBJECTIVES: To compare alpha-galactosidase A activity in dried blood spots on filter paper, plasma, and leukocytes of Fabry disease patients and healthy controls, and to develop a miniaturization approach of the techniques to measure activity using plasma and leukocytes. DESIGN AND METHODS: Blood was collected from healthy controls and Fabry disease patients. Two drops were spotted on filter paper. Plasma and leukocytes were separated from the remaining sample. Enzyme activity was assessed by fluorometry. RESULTS: Significant positive correlation between standard and miniaturized techniques was observed. Alpha-galactosidase activity differed for male and female subjects when analyzed using filter paper and plasma. New reference and cutoff values were established based on the differences in alpha-galactosidase activity between genders. A good correlation was observed across biological materials assessed. CONCLUSIONS: The establishment of specific values for men and women increases reliability of commonly used techniques to screen and diagnose Fabry disease.

New mutations in the GLA gene in Brazilian families with Fabry disease.

Fabry disease (FD) is an X-linked inborn error of glycosphingolipid catabolism that results from mutations in the alpha-galactosidase A (GLA) gene. Evaluating the enzymatic activity in male individuals usually performs the diagnosis of the disease, but in female carriers the diagnosis based only on enzyme assays is often inconclusive. In this work, we analyzed 568 individuals from 102 families with suspect of FD. Overall, 51 families presented 38 alterations in the GLA gene, among which 19 were not previously reported in literature. The alterations included 17 missense mutations, 7 nonsense mutations, 7 deletions, 6 insertions and 1 in the splice site. Six alterations (R112C, R118C, R220X, R227X, R342Q and R356W) occurred at CpG dinucleotides. Five mutations not previously described in the literature (A156D, K237X, A292V, I317S, c.1177_1178insG) were correlated with low GLA enzyme activity and with prediction of molecular damages. From the 13 deletions and insertions, 7 occurred in exons 6 or 7 (54%) and 11 led to the formation of a stop codon. The present study highlights the detection of new genomic alterations in the GLA gene in the Brazilian population, facilitating the selection of patients for recombinant enzyme-replacement trials and offering the possibility to perform prenatal diagnosis.

Fabry disease - importance of screening in cornea verticillata: case report / Doença de Fabry - importância do rastreamento em córnea verticilata: relato de caso

Fabry disease is an X-linked disease of glycosphingolipid (GL) metabolism. The accumulation of GL in tissues can affect multiple organ systems. Initial symptoms includes episodes of severe pain in the extremities, cornea verticillata and skin lesions. In late stages, kidney, heart and brain can be involved. This report attempts for importance of cornea verticillata in the diagnosis of Fabry disease in a young patient with pain in the lower limb extremities.

A doença de Fabry é um erro inato no metabolismo de glicosfingolipides (GL) ligado ao cromossomo X. O acúmulo de GL nos tecidos pode afetar múltiplos órgãos e sistemas. Os sintomas iniciais incluem episódios de dor nas extremidades, córnea verticilata e lesões na pele. Em estágios avançados, os rins, coração e cérebro podem ser envolvidos. Este relato de caso enfatiza para importância da córnea verticilata para o diagnóstico de doença de Fabry em paciente jovem com dor nos membros inferiores.

Influence of pre-analytical factors on α-galactosidase A, arylsulfatase B and α-glucosidase activities measured on dried blood spots on filter paper.

OBJECTIVES: To analyze the effect of blood collection and storage conditions on activity of α-galactosidase A, arylsulfatase B and α-glucosidase. DESIGN AND METHODS: Blood was collected in EDTA, heparin, or direct spotting on filter paper and stored at different temperatures (-20, 4, 25 and 37°C) and storage times (3, 10, 17 and 180 days). The influence of filter paper size was also assessed (3.0 and 1.2mm). RESULTS: No statistically significant difference was observed between the three collection methods. α-Glucosidase A activity significantly decreased after the 10th day, while arylsulfatase B activity only differed significantly after the 180th day, and α-galactosidase A activity remained constant throughout this storage time. Excellent correlation coefficients were observed for the two filter paper sizes used. CONCLUSIONS: Both paper sizes may be employed. Filter paper specimens should be transported under refrigeration as soon as possible after blood collection.

Fabry disease - importance of screening in cornea verticillata: case report.

Fabry disease is an X-linked disease of glycosphingolipid (GL) metabolism. The accumulation of GL in tissues can affect multiple organ systems. Initial symptoms includes episodes of severe pain in the extremities, cornea verticillata and skin lesions. In late stages, kidney, heart and brain can be involved. This report attempts for importance of cornea verticillata in the diagnosis of Fabry disease in a young patient with pain in the lower limb extremities.

Reference values for lysosomal enzymes activities using dried blood spots samples - a Brazilian experience.

BACKGROUND: Lysosomal storage diseases (LSD) are inherited disorders caused by deficiency of lysosomal enzymes in which early diagnosis is essential to provide timely treatment. This study reports interval values for the activity of lysosomal enzymes that are deficient in Mucopolysaccharidosis type I, Fabry, Gaucher and Pompe disease, using dried blood spots on filter paper (DBS) samples in a Brazilian population. RESULTS: Reference activity values were obtained from healthy volunteers samples for alpha-galactosidase A (4.57 ± 1.37 umol/L/h), beta-glucosidase (3.06 ± 0.99 umol/L/h), alpha-glucosidase (ratio: 13.19 ± 4.26; % inhibition: 70.66 ± 7.60), alpha-iduronidase (3.45 ± 1.21 umol/L/h) and beta-galactosidase (14.09 ± 4.36 umol/L/h). CONCLUSION: Reference values of five lysosomal enzymes were determined for a Brazilian population sample. However, as our results differ from other laboratories, it highlights the importance of establishing specific reference values for each center.

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

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.

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.

[Cornea verticillata - a clinical marker of Fabry disease: case report]. / Córnea verticilata - marcador clínico da doença de Fabry: relato de caso.

Fabry's disease is a rare X-linked lysosomal storage disorder of glycosphingolipid (GL) metabolism, caused by a deficiency of alpha-galactosidase A activity. The progressive accumulation of GL in tissues results in the clinical manifestations of the disease, that are more evident in hemizygous males, and include angiokeratomas, acroparesthesia, cornea verticillata, cardiac and kidney involvement, cerebrovascular manifestations. A family with Fabry's disease including 2 female patients and 3 male patients is reported. The patients were submitted to complete medical history, ophthalmological examination and alpha-galactosidase activity test. Cornea verticillata was a constant finding in all patients. This demonstrates the important role of the ophtalmological examination for the diagnosis of Fabry's disease since the eye findings are so characteristic of the disease.

Córnea verticilata - marcador clínico da doença de Fabry: relato de caso / Cornea verticillata - a clinical marker of Fabry disease: case report

A doença de Fabry é erro inato do metabolismo dos glicoesfingolipídeos (GL), resultante da atividade deficiente da enzima alfa-galactosidase A (a-Gal), com herança ligada ao cromossomo X. O acúmulo progressivo de GL nos tecidos resulta nas manifestações clínicas da doença, mais evidentes em homens hemizigotos, e incluem angioqueratomas, acroparestesias, córnea verticilata, hipo-hidrose, envolvimento cardíaco, renal e manifestações cerebrovasculares. Foi realizada avaliação em família acometida pela doença, sendo dois pacientes do sexo feminino e três do sexo masculino. Todos os pacientes foram submetidos a anamnese, exame oftalmológico completo e dosagem da atividade da enzima a-Gal. O único achado clínico presente em todos foi a córnea verticilata. Isto demonstra o importante papel que o exame oftalmológico apresenta no diagnóstico da doença, já que as alterações oculares são tão características.

Fabry's disease is a rare X-linked lisosomal storage disorder of glycosphingolipid (GL) metabolism, caused by a deficiency of alpha-galactosidase A activity. The progressive accumulation of GL in tissues results in the clinical manifestations of the disease, that are more evident in hemizygous males, and include angiokeratomas, acroparesthesia, cornea verticillata, cardiac and kidney involvement, cerebrovascular manifestations. A family with Fabry's disease including 2 female patients and 3 male patients is reported. The patients were submitted to complete medical history, ophthalmological examination and alpha-galactosidase activity test. Cornea verticillata was a constant finding in all patients. This demonstrates the important role of the ophtalmological examination for the diagnosis of Fabry's disease since the eye findings are so characteristic of the disease.