Fabry disease: genetics, pathology, and treatment

SUMMARY Fabry disease (FD) is a recessive monogenic inheritance disease linked to chromosome X, secondary to mutations in the GLA gene. Its prevalence is estimated between 1:8,454 and 1:117,000 among males and is probably underdiagnosed. Mutations in the GLA gene lead to the progressive accumulation of globotriaosylceramide (Gb3). Gb3 accumulates in lysosomes of different types of cells of the heart, kidneys, skin, eyes, central nervous system, and gastrointestinal system, and may lead to different clinical scenarios. The onset of symptoms occurs during childhood, with acroparesthesia, heat intolerance, and gastrointestinal symptoms, such as nausea, vomiting, abdominal pain, and neuropathic pain. Subsequently, symptoms related to progressive impairment appear, such as angiokeratomas, cornea verticillata, left ventricular hypertrophy, myocardial fibrosis, proteinuria, and renal insufficiency. The latter being the main cause of death in FD. The gold standard for diagnosis is the genetic analysis in search of mutation, in addition to family history. In homozygous patients, the enzyme activity can also be used. Once the diagnosis is confirmed, the patient and their family should receive genetic counseling. The treatment, in turn, currently focuses mainly on replacing the enzyme that is absent or deficient by means of enzyme replacement therapy, with the purpose of avoiding or removing deposits of Gb3. Chaperones can also be used for the treatment of some cases. It is considered that the specific treatment should be initiated as soon as a diagnosis is obtained, which can change the prognosis of the disease.

CD77 levels over enzyme replacement treatment in Fabry Disease Family (V269M) / Níveis de CD77 ao longo do tratamento de reposição enzimática em família com Doença de Fabry (V269M)

ABSTRACT Introduction: Fabry disease (FD) is a disorder caused by mutations in the gene encoding for lysosomal enzyme α-galactosidase A (α-GAL). Reduced α-GAL activity leads to progressive accumulation of globotriaosylceramide (Gb3), also known as CD77. The recent report of increased expression of CD77 in blood cells of patients with FD indicated that this molecule can be used as a potential marker for monitoring enzyme replacement therapy (ERT). Objective: The purpose of this study was to evaluate the CD77 levels throughout ERT in FD patients (V269M mutation). Methods: We evaluated the fluctuations in PBMC (peripheral blood mononuclear cell) membrane CD77 expression in FD patients undergoing ERT and correlated these levels with those observed in different cell types. Results: A greater CD77 expression was found in phagocytes of patients compared to controls at baseline. Interestingly, the variability in CD77 levels is larger in patients at baseline (340 - 1619 MIF) and after 12 months of ERT (240 - 530 MIF) compared with the control group (131 - 331 MFI). Furthermore, by analyzing the levels of CD77 in phagocytes from patients throughout ERT, we found a constant decrease in CD77 levels. Conclusion: The increased CD77 levels in the phagocytes of Fabry carriers together with the decrease in CD77 levels throughout ERT suggest that measuring CD77 levels in phagocytes is a promising tool for monitoring the response to ERT in FD.

RESUMO Introdução: A doença de Fabry (DF) é um distúrbio causado por mutações no gene que codifica a enzima lisossômica α-galactosidase A (α-GAL). A redução da atividade de α-GAL leva ao acúmulo progressivo de globotriaosilceramida (Gb3), também conhecida como CD77. O recente relato de aumento da expressão de CD77 em células sanguíneas de pacientes com DF indicou que essa molécula pode ser utilizada como um potencial marcador para o monitoramento da terapia de reposição enzimática (TRE). Objetivo: O objetivo deste estudo foi avaliar os níveis de CD77 ao longo da TRE em pacientes com DF (mutação V269M). Métodos: Foram avaliadas as flutuações na expressão de CD77 nas membranas das CMSP (células mononucleares do sangue periférico) em pacientes com DF submetidos à TRE e correlacionados com aqueles observados em diferentes tipos de células. Resultados: Uma maior expressão de CD77 foi encontrada em fagócitos de pacientes em comparação aos controles no início do estudo. Curiosamente, a variabilidade nos níveis de CD77 é maior em pacientes no início do estudo (340 - 1619 MIF) e após 12 meses de TRE (240 - 530 MIF) em comparação com o grupo controle (131 - 331 MFI). Além disso, analisando os níveis de CD77 em fagócitos de pacientes ao longo da TRE, encontramos uma diminuição constante nos níveis de CD77. Conclusão: O aumento nos níveis de CD77 nos fagócitos de portadores de Fabry, juntamente com a diminuição nos níveis de CD77 ao longo da TRE, sugerem que medir os níveis de CD77 nos fagócitos é uma ferramenta promissora para monitorar a resposta à TRE na DF.

Enfermedad de Fabry Descripción de un caso y su evolución en terapia de reemplazo enzimático / Fabry disease Description of a case and its evolution with enzyme replacement therapy

La enfermedad de Fabry es un trastorno hereditario de depósito lisosomal progresivo y multisistémico del catabolismo de los glicoesfingolípidos, ligado al cromosoma X, que es causado por un defecto en el gen que cataliza la enzima lisosomal alfa-galactosidasa A (alfa-GAL A), y origina el depósito intracelular, especialmente de globotriaosil-ceramida (Gb-3), en el endotelio vascular y otros tejidos. La deficiencia parcial o total de la actividad de la enzima lisosomal conduce a la incapacidad de catabolizar ciertos glicoesfingolípidos causando el daño principal, es decir, el depósito intralisosomal de sustrato Gb-3 en diferentes tipos de células. En particular, son afectadas progresivamente las células vasculares endoteliales, lo cual puede causar isquemia tisular e infarto. Es una enfermedad progresiva que causa manifestaciones derivadas de la disfunción del órgano afectado por los depósitos, principalmente riñón, corazón, sistema nervioso, tracto gastrointestinal y piel, aunque puede participar cualquier órgano y sistema de la economía. Antes de la disponibilidad de la terapia de reemplazo enzimático, el tratamiento para esta enfermedad consistía principalmente de cuidados sintomáticos y medidas correctivas no específicas. Se describen las características clínicas y la evolución de un hombre de 47 años con enfermedad de Fabry en terapia de reemplazo enzimático. (ActaMed Colomb 2014; 39: 202-206).

Fabry disease is an inherited disorder of progressive and multisystemic lysosomal storage of glycosphingolipids catabolism, X-linked, which is caused by a defect in the gene that catalyzes the lysosomal enzyme alpha-galactosidase A (alpha-GAL A), and causes the intracellular deposition, especially of globotriaosyl ceramide (Gb3) in the vascular endothelium and other tissues. Partial or total deficiency of the lysosomal enzyme activity leads to the inability to catabolize certain glycosphingolipids causing the main damage, namely the intralysosomal deposit of Gb3 substrate in different cell types. In particular, vascular endothelial cells are progressively affected, which may cause tissue ischemia and infarction. It is a progressive disease that causes manifestations derived from the dysfunction of the organ affected by the deposits, mainly kidney, heart, nervous system, gastrointestinal tract and skin, although any organ and system of the economy may be involved. Before the availability of enzyme replacement therapy, treatment for this condition consisted mainly of symptomatic care and no specific remedies. Clinical characteristics and evolution of a 47 year old man with Fabry disease on enzyme replacement therapy are described. (Acta Med Colomb 2014; 39: 202-206).

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.

Enfermedad de Fabry-Anderson: angioqueratomas: acroparestesias / Disease of Fabry-Anderson: angioqueratomas: acroparestesias

Paciente de sexo masculino de 32 años de edad que consulta al Servicio de Dermatología por angioqueratomas diseminados y acroparestesias de 20 años de evolución. Con la sospecha de enfermedad de Fabry-Anderson, se solicita dosaje enzimático de alta galactosidasa A, confirmando el diagnóstico.

Short-Term Efficacy of Enzyme Replacement Therapy in Korean Patients with Fabry Disease

Fabrazyme has been widely used for treatment of Fabry disease since its approval by the U.S. Food and Drug Administration in 2003. This study was undertaken to assess the short-term efficacy and safety of enzyme replacement therapy (ERT) for Fabry disease in Korea. Eight male patients and three female symptomatic carriers aged 13 to 48 yr were included. Fabrazyme was administered by intravenous infusion at a dose of 1 mg/kg every 2 weeks. Plasma and urine globotriaosylceramide (GL-3) levels, serum creatinine, creatinine clearance, and 24-hr urine protein levels were measured every 3 months. Kidney biopsies, ophthalmologic exams, and pure tone audiometry were performed before and 1 yr after ERT. Kidney function, including serum creatinine, creatinine clearance, and the 24-hr urine protein level, remained stable during ERT. Plasma and urine GL-3 levels were reduced within 3 to 6 months of ERT initiation. Microvascular endothelial deposits of GL-3 were decreased from renal biopsy specimens after 1 yr of treatment. The severity of sensorineural hearing loss and tinnitus did not improve after ERT. ERT is safe and effective in stabilizing renal function and clearing microvascular endothelial GL-3 from kidney biopsy specimen in Korean patients with Fabry disease.

Epigallocatechin-3-gallate Suppresses Galactose-alpha1,4-galactose-beta1,4-glucose Ceramide Expression in TNF-alpha Stimulated Human Intestinal Epithelial Cells Through Inhibition of MAPKs and NF-kappa B

Intestinal epithelial cells (IECs) have been known to produce galactose-alpha1,4-galactose-beta1,4-glucose ceramide (Gb3) that play an important role in the mucosal immune response. The regulation of Gb3 is important to prevent tissue damage causing shiga like toxin. Epigallocatechin-3-gallate (EGCG) has been studied as anti-carcinogenic, anti-oxidant, anti-angiogenic, and anti-viral activities, and anti-diabetic. However, little is known between the expressions of Gb3 on IECs. The aim of this study was to examine the inhibitory effect of EGCG, a major ingredient of green tea, on Gb3 production via mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-kappa B) in the TNF-alpha stimulated human colon epithelial cells, HT29. To investigate how Gb3 is regulated, ceramide glucosyltransferase (CGT), lactosylceramide synthase (GalT2), and Gb3 synthase (GalT6) were analyzed by RT-PCR in HT 29 cells exposed to TNF-alpha in the presence or absence of EGCG. EGCG dose-dependently manner, inhibits TNF-alpha induced Gb3 expression by blocking in both the MAPKs and NF-kappaB pathways in HT29 cells. TNF-alpha enhanced CGT, GalT2 and GalT6 mRNA levels and EGCG suppressed the level of these enzymes enhanced by TNF-alpha treatment.