Fabry's disease pathophysiology
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Sukaina Furniturewala, MBBS[2]
Overview
Genes involved in the pathogenesis of Fabry's disease include the GLA gene, which codes the important enzyme of alpha-galactosidase. The absence or lack of this enzyme causes Gb3 accumulation in different organs. The main pathological finding is detection of these inclusion in different cells with electron microscopies.
Pathophysiology
Physiology
- GLA gene codes information for the alpha-galactosidase enzyme.
- The normal function of the alpha-galactosidase enzyme is to breakdown globotriaosylceramide (also abbreviated as Gb3, GL-3, or ceramide trihexoside) into glucocerebroside in lysosomes.
- Gb3 is produced in the catabolism pathway of Globoside, an essential glycosphingolipid in the cell membrane (RBCs and Kidney), that is mainly metabolized in the lysosome of the spleen, liver , and bone marrow.[1]
Pathogenesis
- Fabry disease is caused by a deficiency of alpha-galactosidase.
- Mutations to the GLA gene encoding α-GAL may result in a complete loss of function of the enzyme.
- Alpha-galactosidase is a lysosomal protein responsible for breaking down globotriaosylceramide(Gb3) a fatty substance stored in various types of cardiac and renal cells.[2]
- Improper catabolism causes globotriaosylceramide (Gb3) to accumulate in cells lining blood vessels in the skin, kidney, heart, and nervous system. As a result, signs, and symptoms of Fabry diseasseven begin to manifest.[3]
- Accumulation of globotriaosylceramide (Gb3) in different tissues leads to cellular death, compromised energy metabolism, small vessel injury, potassium-calcium channel dysfunction in the endothelial cells, oxidative stress,impaired autophagosome maturation, tissue ischemia, irreversible cardiac and renal tissue fibrosis.[4]
Genetics
- Fabry's disease follows an X-linked inheritance pattern.
- Since it is inherited in an X-linked pattern, males are homozygous and pass the disease to all daughters but no sons.
- Females are heterozygous with 50% chance of passing the mutated gene to both daughters and sons.[5]
- Skewed nonrandom X chromosome inactivation may cause paradoxical nature of the disease that is seen in females,; they have a varied presentation from being asymptomatic to having very severe symptoms and having a presentation similar to that seen in males with the classical type.[6]
- Gene function: GLA gene encodes information for alpha-Gal-A.
- Gene location: GLA has its locus located on the Longarm of chromosome X in position Xq22. It has seven exons distributed over 1290 base pairs of coding part. [7][8]
- Demonstrates extensive allelic heterogeneity but no genetic locus heterogeneity.[9]
- 585 mutations have so far been recorded for Fabry's disease.[10]
- Mutations demonstrated include Missense, Non-sense point mutations,splicing mutations, small deletion/Insertion, and large deletions.[11]
Gross pathology
- The most important characteristics of Fabry's disease on gross pathology are:
- Kidney
- Kidney enlargement
- Renal cysts of cortical and parapelvic
- Decreased cortical thickness[12]
- Heart
- Four chamber cardiomegaly( frequently LVH with interventricular septum hypertrophy)[13]
- Eye
- Conjunctiva
- Ampullary and saccular aneurysms of small venules
- Thrombosis[14]
- Retina
- Segmental dilatation and tortuosity of venules and arteries
- Whorl-like corneal dystrophic pattern[15]
- Conjunctiva
- Nervous system
- Central nervous system
- White matter lesion [16]
- Central nervous system
- Kidney
Microscopic pathology
General
On microscopic histopathological analysis, tissue deposition of glycosphingolipids crystalline is a characteristic finding of Fabry's disease.
- Glycosphingolipid inclusions morphology: coarsely lamellated appearance, maybe round with onion-skin likes structure (Myelin figures), or dense unstructured layer (Zebra bodies), some can be dark electrodense and amorphous especially in endothelial and mesangial cells.
- Electron Microscopy: The most accurate method for detection of glycosphingolipids depositions. preserved whole glycosphingolipids during the preparation process.
- Light microscopy is not as specific in confirming FD as electron microscopy and thus is only done when electron microscopy is unavailable.
Light microscopy | |||
---|---|---|---|
Paraffin-embedded sections | H&E staining | Cytoplasm vacuolation
(swollen appearance) |
Characteristic but not pathognomonic |
Jones methenamine silver (JMS) staining | granular and argyrophilic inclusions | due to the residual carbohydrate part of glycosphingolipids | |
Methacrylate-embedded sections | Lipid-soluble dye | glycosphingolipids inclusions | not routine |
Frozen section | Allows preservation but may lose dome details | ||
Epon-embedded sections | Toluidine blue | dark blue and dark gray round spiral inclusions | detect entire glycosphingolipids |
Methylene blue |
- Immunofluorescence Microscopy: Negative, not react to IgG, IgM, IgA, C3, C1q antibodies.
- Immunohistochemistry: Murine anti-Gb3 antibody id used.
Organs
Organs | Light microscope | Electron microscope |
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Skin (Angiokeratoma) |
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Kidney |
Urinary sediment
Organ Histology
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Heart |
|
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Ocular system |
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Nervous System |
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References
- ↑ Tuttolomondo A, Simonetta I, Riolo R, Todaro F, Di Chiara T, Miceli S; et al. (2021). "Pathogenesis and Molecular Mechanisms of Anderson-Fabry Disease and Possible New Molecular Addressed Therapeutic Strategies". Int J Mol Sci. 22 (18). doi:10.3390/ijms221810088. PMC 8465525 Check
|pmc=
value (help). PMID 34576250 Check|pmid=
value (help). - ↑ Kok K, Zwiers KC, Boot RG, Overkleeft HS, Aerts JMFG, Artola M (2021). "Fabry Disease: Molecular Basis, Pathophysiology, Diagnostics and Potential Therapeutic Directions". Biomolecules. 11 (2). doi:10.3390/biom11020271. PMC 7918333 Check
|pmc=
value (help). PMID 33673160 Check|pmid=
value (help). - ↑ Tuttolomondo A, Simonetta I, Riolo R, Todaro F, Di Chiara T, Miceli S; et al. (2021). "Pathogenesis and Molecular Mechanisms of Anderson-Fabry Disease and Possible New Molecular Addressed Therapeutic Strategies". Int J Mol Sci. 22 (18). doi:10.3390/ijms221810088. PMC 8465525 Check
|pmc=
value (help). PMID 34576250 Check|pmid=
value (help). - ↑ Tuttolomondo A, Simonetta I, Riolo R, Todaro F, Di Chiara T, Miceli S; et al. (2021). "Pathogenesis and Molecular Mechanisms of Anderson-Fabry Disease and Possible New Molecular Addressed Therapeutic Strategies". Int J Mol Sci. 22 (18). doi:10.3390/ijms221810088. PMC 8465525 Check
|pmc=
value (help). PMID 34576250 Check|pmid=
value (help). - ↑ Adam MP, Ardinger HH, Pagon RA, Wallace SE, Bean LJH, Gripp KW; et al. (1993). "GeneReviews®". PMID 20301469.
- ↑ Echevarria L, Benistan K, Toussaint A, Dubourg O, Hagege AA, Eladari D; et al. (2016). "X-chromosome inactivation in female patients with Fabry disease". Clin Genet. 89 (1): 44–54. doi:10.1111/cge.12613. PMID 25974833.
- ↑ Mehta A, Beck M, Sunder-Plassmann G (2006). "Fabry Disease: Perspectives from 5 Years of FOS". PMID 21290673.
- ↑ Eng CM, Desnick RJ (1994). "Molecular basis of Fabry disease: mutations and polymorphisms in the human alpha-galactosidase A gene". Hum Mutat. 3 (2): 103–11. doi:10.1002/humu.1380030204. PMID 7911050.
- ↑ Mehta A, Beck M, Sunder-Plassmann G (2006). "Fabry Disease: Perspectives from 5 Years of FOS". PMID 21290673.
- ↑ Germain DP (2010). "Fabry disease". Orphanet J Rare Dis. 5: 30. doi:10.1186/1750-1172-5-30. PMC 3009617. PMID 21092187.
- ↑ Mehta A, Beck M, Sunder-Plassmann G (2006). "Fabry Disease: Perspectives from 5 Years of FOS". PMID 21290673.
- ↑ Glass RB, Astrin KH, Norton KI, Parsons R, Eng CM, Banikazemi M; et al. (2004). "Fabry disease: renal sonographic and magnetic resonance imaging findings in affected males and carrier females with the classic and cardiac variant phenotypes". J Comput Assist Tomogr. 28 (2): 158–68. doi:10.1097/00004728-200403000-00002. PMID 15091117.
- ↑ Frustaci A, Chimenti C (2007). "Images in cardiovascular medicine. Cryptogenic ventricular arrhythmias and sudden death by Fabry disease: prominent infiltration of cardiac conduction tissue". Circulation. 116 (12): e350–1. doi:10.1161/CIRCULATIONAHA.107.723387. PMID 17875975.
- ↑ Velzeboer CM, de Groot WP (1971). "Ocular manifestations in angiokeratoma corporis diffusum (Fabry)". Br J Ophthalmol. 55 (10): 683–92. doi:10.1136/bjo.55.10.683. PMC 1208523. PMID 5124844.
- ↑ Velzeboer CM, de Groot WP (1971). "Ocular manifestations in angiokeratoma corporis diffusum (Fabry)". Br J Ophthalmol. 55 (10): 683–92. doi:10.1136/bjo.55.10.683. PMC 1208523. PMID 5124844.
- ↑ Fellgiebel A, Müller MJ, Mazanek M, Baron K, Beck M, Stoeter P (2005). "White matter lesion severity in male and female patients with Fabry disease". Neurology. 65 (4): 600–2. doi:10.1212/01.wnl.0000173030.70057.eb. PMID 16116124.
- ↑ Cable WJ, Dvorak AM, Osage JE, Kolodny EH (1982). "Fabry disease: significance of ultrastructural localization of lipid inclusions in dermal nerves". Neurology. 32 (4): 347–53. doi:10.1212/wnl.32.4.347. PMID 6278363.