Ophthalmological manifestations of Fabry disease: a survey of patients at the Royal Melbourne Fabry Disease Treatment Centre

Tomographic, Biomechanical, and In Vivo Confocal Microscopic Changes in Cornea in Chronic Gout Disease

PURPOSE

This study aimed to evaluate the tomographic, biomechanical, and in vivo confocal microscopic (IVCM) effects of chronic gout disease on human cornea.

METHODS

This prospective study included 60 eyes of 30 participants with chronic gout disease and 60 eyes of 30 healthy controls. Corneal thickness, keratometry (K) readings, and corneal aberrations were measured with Sirius 3 D corneal tomography system (Sirius, CSO, Italy). Corneal biomechanical properties (corneal hysteresis [CH], corneal resistance factor [CRF], and intraocular pressure [IOP] parameters) were assessed with an ocular response analyzer (ORA, Reichert Ophthalmic Instruments). The number and morphology of corneal endothelial cells and the number of basal epithelial cells were evaluated with IVCM (Confoscan 4.0). Tear breakup time (TBUT) was also evaluated.

RESULTS

The mean diagnosis time of the patients with gout was 91.2 ± 69.6 months (12-300 month). Among corneal tomography measurements, K readings were similar between the two groups, while total and higher-order aberrations(coma, trefoil,s pherical, and quadrafoil) were significantly higher in the gout group. In the evaluation of biomechanical measurements, the CH value was significantly lower and the corneal-compensated IOP value was significantly higher in the gout group (p = 0.02, p = 0.01, respectively). The two groups did not significantly differ regarding the CRF or Goldmann IOP (p = 0.61, p = 0.15, respectively). Among the IVCM parameters, the number of corneal basal epithelial cells and the percentage of corneal endothelial hexagonality were significantly lower in the gout group, but no significant difference was detected in terms of the number of endothelial cells or polymegathism (p = 0.02, p < 0.001, p = 0.18, p = 0.59, respectively). While TBUT was significantly lower in the gout group (p < 0.001).

CONCLUSION

This study showed that chronic gout disease increases the corneal aberrations and decreases the basal epithelial cell count, hexagonality ratio of endothelial cell and corneal biomechanics.

Atypical Presentation of Vitreous Inflammation in a Patient With Hypertensive Retinopathy

Purpose: To describe an atypical presentation of vitreous inflammation in a patient with malignant hypertension. Methods: A case was evaluated. Results: A patient presenting with a hypertensive emergency was found to have decreased vision in the setting of severe optic nerve head edema, extensive hard exudates, cotton-wool spots, and Elschnig spots in both eyes secondary to malignant hypertension as well as vitreous cells bilaterally. He was admitted to the pediatric intensive care unit for intravenous medications and observation. Conclusions: This case adds to the growing body of evidence suggesting that hypertensive urgency may be accompanied by inflammation.

Ocular manifestations of the genetic causes of focal and segmental glomerulosclerosis

Genetic forms of focal and segmental glomerulosclerosis (FSGS) often have extra-renal manifestations. This study examined FSGS-associated genes from the Genomics England Renal proteinuria panel for reported and likely ocular features. Thirty-two of the 55 genes (58%) were associated with ocular abnormalities in human disease, and a further 12 (22%) were expressed in the retina or had an eye phenotype in mouse models. The commonest genes affected in congenital nephrotic syndrome (NPHS1, NPHS2, WT1, LAMB2, PAX2 but not PLCE1) may have ocular manifestations . Many genes affected in childhood-adolescent onset FSGS (NPHS1, NPHS2, WT1, LAMB2, SMARCAL1, NUP107 but not TRPC6 or PLCE1) have ocular features. The commonest genes affected in adult-onset FSGS (COL4A3-COL4A5, GLA ) have ocular abnormalities but not the other frequently affected genes (ACTN4, CD2AP, INF2, TRPC6). Common ocular associations of genetic FSGS include cataract, myopia, strabismus, ptosis and retinal atrophy. Mitochondrial forms of FSGS (MELAS, MIDD, Kearn's Sayre disease) are associated with retinal atrophy and inherited retinal degeneration. Some genetic kidney diseases (CAKUT, ciliopathies, tubulopathies) that result in secondary forms of FSGS also have ocular features. Ocular manifestations suggest a genetic basis for FSGS, often help identify the affected gene, and prompt genetic testing. In general, ocular abnormalities require early evaluation by an ophthalmologist, and sometimes, monitoring or treatment to improve vision or prevent visual loss from complications. In addition, the patient should be examined for other syndromic features and first degree family members assessed.

Correlation of retinal vascular characteristics with laboratory and ocular findings in Fabry disease: exploring ocular diagnostic biomarkers

BACKGROUND

The goal of this study was to evaluate macular microvascular changes in patients with Fabry disease (FD) using optical coherence tomography angiography (OCTA) and to explore their correlation with laboratory and ocular findings.

METHODS

A total of 76 eyes (38 patients) and 48 eyes of 24 healthy controls were enrolled in this prospective study. Vessel Area Density (VAD) and Foveal Avascular Zone (FAZ) area were calculated on 2.9 × 2.9 mm OCTA images scanned with the Heidelberg Spectralis II (Heidelberg, Germany). VAD was measured in three layers: Superficial Vascular Plexus (SVP), Intermediate Capillary Plexus (ICP), and Deep Capillary Plexus (DCP). All scans were analyzed with the EA-Tool (Version 1.0), which was coded in MATLAB (The MathWorks Inc, R2017b). FAZ area was manually measured in full-thickness, SVP, ICP and DCP scans.

RESULTS

Average VAD in SVP, ICP and DCP was higher in Fabry disease patients than in controls (49.4 ± 11.0 vs. 26.5 ± 6.2, 29.6 ± 7.4 vs. 20.2 ± 4.4, 32.3 ± 8.8 vs. 21.7 ± 5.1 respectively, p < 0.001). Patients with cornea verticillata (CV) had a higher VAD in ICP and DCP compared to patients without CV (p < 0.01). Patients with increased lysoGb3 concentration had a higher VAD in DCP when compared to patients with normal lysoGb3 concentration (p < 0.04). There was no difference in VAD in patients with and without vascular tortuosity. However, a significantly higher VAD was observed in patients with vascular tortuosity compared to controls (p < 0.03).

CONCLUSIONS

Increased lysoGb3 and VAD in DCP could be reliable biomarkers of disease activity. Cornea verticillata could be adopted as a predictive biomarker for VAD changes and disease progression. The combination of cornea verticillata and increased VAD may serve as a diagnostic biomarker for Fabry disease, however due to the discrepancies in VAD values in various studies, further research has to be done to address this claim.

Investigation of OCTA Biomarkers in Fabry Disease: A Long Term Follow-Up of Macular Vessel Area Density and Foveal Avascular Zone Metrics

INTRODUCTION

Retinal microvasculature is known to be altered in patients with Fabry disease (FD). We aimed to investigate the long-term changes in macular microvasculature and explore a reliable retinal biomarker for treatment monitoring in FD.

METHODS

Prospective study of 26 eyes with FD followed up to 48 months (mean 24, range 8-48). OCT angiography (OCTA) images (2.9 × 2.9 mm) were obtained using Heidelberg Spectralis II at baseline and follow-up. Macular vessel area density (VAD, %) was measured in three layers: superficial vascular plexus (SVP), intermediate capillary plexus (ICP) and deep capillary plexus (DCP) in three peri-macular circular sectors (c1, c2, c3). Additionally, foveal avascular zone (FAZ) area (mm2) and horizontal and vertical diameters (µm) were assessed.

RESULTS

VAD decreased over time in SVP, ICP (in sectors c2 and c3) and DCP (all sectors) (p < 0.04). VAD reduction was predominantly seen in treated FD patients. FAZ and horizontal diameters increased at follow-up in FD patients compared to baseline (p ≤ 0.025). Correlation analysis showed a moderate to strong negative correlation between VAD of SVP and DCP in the innermost circle and FAZ in treated patients (r = - 0.6; p < 0.0001).

CONCLUSIONS

This is the first long-term follow-up OCTA study in FD to our knowledge. A decrease in VAD, pronounced in the peripheral circle and deeper layers, as well as an enlargement of the FAZ could be observed over time. These changes reflect the vascular remodelling during the course of the disease. Interestingly, the reduction of VAD was more pronounced in treated patients. This could be a result of enzyme replacement therapy and could be potentially used as a reliable biomarker for monitoring the treatment of the disease. A baseline examination of VAD and FAZ before treatment initiation is meaningful. Larger studies are needed to establish the use of VAD and FAZ as biomarkers for treatment monitoring.

Ophthalmic Manifestations in Fabry Disease: Updated Review

Fabry disease (FD) is an X-linked lysosomal storage disorder, causing Gb-3 (globotriaosylceramide) buildup in cellular lysosomes throughout the body, in particular in blood vessel walls, neuronal cells, and smooth muscle. The gradual accumulation of this glycosphingolipid in numerous eye tissues causes conjunctival vascular abnormalities, corneal epithelial opacities (cornea verticillata), lens opacities, and retinal vascular abnormalities. Although a severe vision impairment is rare, these abnormalities are diagnostic indicators and prognostics for severity. Cornea verticillata is the most common ophthalmic feature in both hemizygous men and heterozygous females. Vessel tortuosity has been linked to a faster disease progression and may be useful in predicting systemic involvement. New technologies such as optical coherence tomography angiography (OCTA) are useful for monitoring retinal microvasculature alterations in FD patients. Along with OCTA, corneal topographic analysis, confocal microscopy, and electro-functional examinations, contributed to the recognition of ocular abnormalities and have been correlated with systemic involvement. We offer an update regarding FD ocular manifestations, focusing on findings derived from the most recent imaging modalities, to optimize the management of this pathology.

Ocular findings and their correlation with disease severity in Fabry disease in South-East Anatolia

PURPOSE

To evaluate the ocular findings and the relationship between these findings and the disease severity of patients with Fabry disease (FD) in South-East Anatolia.

METHODS

We enrolled the 24 eyes of 24 patients with FD and the disease severity scores were obtained with FD severity scoring system (DS3). The relationship between the presence of any ocular findings and DS3 scores was evaluated.

RESULTS

The mean age of the patients was 35.2 ± 8.6 years. The mean DS3 score and α-galactosidase A enzyme activity of the patients was 7.04 ± 3.71 and 1.93 ± 0.84 μmol/l/h, respectively. Of the 24 patients, 20 (83.3%) had cornea verticillate (CV), 18 (75%) had tortuous conjunctival vessels, 15 (62.5%) had tortuous retinal vessels and 3 (12.5%) had lens opacities. The ocular vascular abnormalities were associated with disease severity (p < 0.05); however, the presence of CV did not affect the DS3 scores (p > 0.05).

CONCLUSIONS

According to our study, the patients with ocular vascular abnormalities associated with FD had more severe disease than those who did not have an abnormality. CV was the most common ocular finding in FD, but it has no association with disease severity.

Autophagy-lysosome pathway alteration in ocular surface manifestations in Fabry disease patients

Background

Fabry disease (FD) is a rare X-linked, lysosomal storage disorder caused by mutations in the alpha-galactosidase gene and characterized by neurological, cutaneous, renal, cardiovascular, cochleo-vestibular and ocular manifestations. The aim of this study is to characterize morphological, functional and autophagy-lysosome pathway alterations of the ocular surface in FD patients.

Methods

Eleven subjects with a diagnosis of FD and fifteen healthy control subjects were examined. All patients underwent ocular surface slit lamp examination, corneal aesthesiometry and in vivo confocal laser-scanning microscopy (CCM). Conjunctival impression cytology was performed in six FD patients and six controls, to assess for expression of two markers of the autophagy-lysosome pathway: the microtubule-associated protein light chain 3 (LC3) and lysosome-associated membrane protein 2 (LAMP2).

Results

Cornea verticillata and increased conjunctival vessel tortuosity were detected respectively in 67% and 33% of patients with FD. Compared with healthy subjects, patients affected by FD showed a significant reduction in corneal nerve fiber length, density and nerve branching on CCM and a significantly increased expression of LC3 on conjunctival impression cytology (p < 0.001). No changes were observed in the conjunctival expression of LAMP2 between the two groups.

Conclusions

This study shows that FD is associated with ocular surface alterations including corneal and conjunctival morphology, innervation and vascularization changes. Our data demonstrate an increased expression of LC3 protein in patients with FD, suggesting that alteration of the autophagy-lysosome pathway may play a role in the occurrence of ocular manifestations.

Expert opinion on the recognition, diagnosis and management of children and adults with Fabry disease: a multidisciplinary Turkey perspective

This consensus statement by a panel of Fabry experts aimed to identify areas of consensus on conceptual, clinical and therapeutic aspects of Fabry disease (FD) and to provide guidance to healthcare providers on best practice in the management of pediatric and adult patients with FD. This consensus statement indicated the clinical heterogeneity of FD as well as a large number of pathogenic variants in the GLA gene, emphasizing a need for an individualized approach to patient care. The experts reached consensus on the critical role of a high index of suspicion in symptomatic patients and screening of certain at-risk groups to reveal timely and accurate diagnosis of FD along with an increased awareness of the treating physician about the different kinds of pathogenic variants and their clinical implications. The experts emphasized the crucial role of timely recognition of FD with minimal delay from symptom onset to definite diagnosis in better management of FD patients, given the likelihood of changing the disease's natural history, improving the patients' quality of life and the prognosis after enzyme replacement therapy (ERT) administered through a coordinated, multidisciplinary care approach. In this regard, this consensus document is expected to increase awareness among physicians about unique characteristics of FD to assist clinicians in recognizing FD with a well-established clinical suspicion consistent with pathogenic variants and gender-based heterogeneous clinical manifestations of FD and in translating this information into their clinical practice for best practice in the management of patients with FD.

Vascular and structural analyses of retinal and choroidal alterations in Fabry disease: the effect of hyperreflective foci and retinal vascular tortuosity

PURPOSE

To evaluate the effects of Fabry disease (FD) on the retinal microvasculature and choroidal vascular and structural characteristics.

METHODS

This study included 10 patients with FD and 10 age-matched healthy controls. Binarized enhanced depth imaging optical coherence tomography (OCT) images were used to measure the total choroidal area, luminal area, and stromal area with ImageJ software. The choroidal vascularity index (CVI) was assessed. The vessel densities (VD) of the retinal capillary plexuses and foveal avascular zone (FAZ) area were measured with OCT-angiography.

RESULTS

The most common anterior segment finding was cornea verticillata (60.0%) and the most frequent posterior segment finding was vascular tortuosity (50.0%). Intraretinal hyperreflective foci on B-scan OCT was observed in 50.0% of the cases. In Fabry cases, a linear mixed model with random intercept revealed that 1% change in CVI was related to -0.009 mm² (p = .015) change in FAZ area and -0.047 mm change, (p = .024) in FAZ perimeter. In the presence of retinal vascular tortuosity, 1% change in CVI was related to -0.013 mm² (p = .002) change in FAZ area and -0.052 mm change (p = .004) in FAZ perimeter. In the presence of hyperreflective foci, 1% change in CVI was related to -0.014 mm² (p = .004) change in FAZ area and -0.064 mm change (p = .003) in FAZ perimeter.

CONCLUSION

The significant negative associations between FAZ measurements and CVI suggest a possible interaction between the choroidal and retinal microvasculature of patients with FD. These alterations were more pronounced in the presence of hyperreflective foci and retinal vascular tortuosity.

Variable clinical features of patients with Fabry disease and outcome of enzyme replacement therapy

Fabry disease (FD) is an X-linked lysosomal storage disorder caused by a deficiency in the enzyme α-galactosidase A due to mutations in the GLA gene. This leads to an accumulation of globotriaosylceramide (GL-3) in many tissues, which results in progressive damage to the kidneys, heart, and nervous system. We present the molecular and clinical characteristics and long-term outcomes of FD patients from a multidisciplinary clinic at the University of California, Irvine treated with agalsidase beta enzyme replacement therapy (ERT) for 2-20 years. This cohort comprised 24 adults (11 males, 13 females) and two male children (median age 45; range 10-68 years). Of the 26 patients in this cohort, 20 were on ERT (12 males, 8 females). We describe one novel variant not previously reported in the literature in a patient with features of 'classic' FD. The vast majority of patients in this cohort presented with symptoms of 'classic' FD including peripheral neuropathic pain, some form of cardiac involvement, angiokeratomas, corneal verticillata, hypohidrosis, tinnitus, and gastrointestinal symptoms, primarily abdominal pain. The majority of males had clinically evident renal involvement. An annual eGFR reduction of -1.88 mL/min/1.73 m2/yr during the course of ERT was seen in this cohort. The most common renal presentation was proteinuria, and one individual required a renal transplant. Other common findings were pulmonary involvement, lymphedema, hearing loss, and significantly, three patients had strokes. Notably, there was a high prevalence of endocrine dysfunction and low bone mineral density, including several with osteoporosis. While enzyme replacement therapy (ERT) cleared plasma GL-3 in this cohort, there was limited improvement in renal function or health-related quality of life based on the patient-reported SF-36 Health Survey. Physical functioning significantly declined over the course of ERT treatment, which may be, in part, due to the late initiation of ERT in several patients. Further delineation of the phenotypic and genotypic spectrum in patients with FD and the long-term outcome of ERT will help improve management and treatment options for this disease.

The Retinal Vessel Density as a New Vascular Biomarker in Multisystem Involvement in Fabry Disease: An Optical Coherence Tomography Angiography Study

In this study, we evaluated the possible relationship between the changes in retinal vessel density (VD) by optical coherence tomography angiography (OCTA) and the vascular alterations involving renal, cardiovascular and central nervous systems in patients affected by Fabry disease (FD). In 50 FD patients, the retinal superficial capillary plexus (SCP) and deep capillary plexus (DCP) in macular region were evaluated by OCTA examination. The patients also underwent a brain magnetic resonance imaging scan, renal and echocardiographic examinations with quantification of systolic pulmonary arterial pressure (PAPs) and left atrial volume index (LAVi). The VD of SCP and DCP was inversely related with E/e’ ratio, LAVi, interventricular septal thickness, global longitudinal strain (GLS) and PAPs (p < 0.05). No relationship was found, with a multivariate analysis, between OCTA parameters and kidney function and neuroradiological signs of central nervous system involvement. OCTA could be a new vascular biomarker in FD, revealing a strong correlation between retinal capillary damage and myocardial impairment, possibly preceding both renal dysfunction and cerebrovascular involvement.

Corneal densitometry: a potential indicator for early diagnosis of Fabry disease

Purpose

To assess corneal densitometry in patients with Fabry disease (FD) and to compare corneal densitometry differences in FD patients to different corneal manifestations.

Methods

Ten participants (20 eyes) with FD and 10 age-matched healthy volunteers (20 eyes) were recruited. All participants were assessed by standardized ophthalmic examinations and the corneal densitometry analysis by Pentacam HR. Densitometry measurements were analyzed in standardized grayscale units.

Results

Seven patients developed conjunctival vessel tortuosity, cornea verticillata appeared in 6 patients, and two patients had Fabry cataract. Retinal vessel tortuosity occurred in 4 patients, and dilation of retinal vessels appeared in 3 patients, all symptoms occurred in both eyes. The first diagnosis of FD up to examination was 4.7 ± 3.23 years, and first ERT up to examination was 2.6 ± 2.27 years. The initial time to diagnosis was negatively related to the corneal densitometry value of the 0–2-mm (r = − 0.556, p = 0.011) and 2–6-mm (r = − 0.482, p = 0.032) zones in the posterior layer. FD group have significantly higher corneal densitometry in anterior 0–2-mm zone and 2–10-mm zone anterior and posterior layer than the control group (p ≤ 0.035, respectively). When divided into two groups by the existence of cornea verticillata, there was a statistically significant difference in the anterior layer, 6–10-mm zone (p = 0.031); in the central layer, 0–2 mm (p = 0.012), 2–6 mm (p = 0.001), 6–10 mm (p = 0.002), and total (p = 0.002); and in the posterior layer, 6–10 mm (p = 0.004) and total (p = 0.002).

Conclusions

FD patients show higher corneal densitometry, and corneal densitometry may have potential for early diagnosis and reminding progress of FD.

Optical coherence tomography angiography analysis of fabry disease

PURPOSE

Fabry disease (FD) is characterized by a deficiency in α-galactosidase A activity that leads to the cumulative deposition of unmetabolized glycosphingolipids within organs, including the vascular endothelium and the eyes. The purpose of this study was to assess the effects of FD on the retinal microvasculature, foveal avascular zone (FAZ), macular thickness and retinal nerve fiber layer (RNFL) using optical coherence tomography angiography (OCT-A).

METHODS

Twenty-five patients (14 female and 11 male; mean age 33.16 ± 11.44) with genetically verified FD were compared with 37 age- and sex-matched healthy controls (mean age 32.36 ± 15.54). The vessel density (VD) values of the superficial and deep capillary plexuses (SCP and DCP), the area of the FAZ, the density of radial peripapillary capillaries (RPC), the macular thickness and the retinal nerve fiber layer thickness were measured by OCT-A examination.

RESULTS

The patients showed significantly lower VD values than controls in the foveal regions of both SCP and the DCP (21.15 ± 5.56 vs. 23.79 ± 4.64 (p = 0.048), 37.92 ± 6.78 vs. 41.11 ± 5.59 (p = 0.048), respectively). The FAZ was significantly larger in the FD group than in the control group (0.3 ± 0.1 vs. 0.24 ± 0.08 (p = 0.011)). No significant difference was identified in measurements of RPC density, peripapillary RNFL thickness or macular thickness between the two groups (p > 0.05 for all).

CONCLUSION

Decreased VD and an enlarged foveal avascular area suggest possible changes in the retinal microvasculature of patients with FD. OCT-A can serve as a useful, noninvasive, quantitative tool for diagnosing FD and monitoring its progression.

Retinal hyperreflective foci in Fabry disease

Background

Fabry disease (FD) is an X-linked inherited storage disorder caused by deficiency of lysosomal alpha-Galactosidase A. Here we describe new retinal findings in patients with FD assessed by Spectral domain optical coherence tomography (SD-OCT) and their possible clinical relevance.

Methods

54 eyes of 27 FD patients and 54 eyes of 27 control subjects were included. The ophthalmic examination included visual acuity testing, tonometry, slit lamp and fundus examination. SD-OCT imaging of the macula was performed in all subjects. Central retinal thickness and retinal nerve fiber layer analysis were quantified. Vessel tortuosity was obtained by a subjective scoring and mathematically calculated. Inner retinal hyperreflective foci (HRF) were quantified, clinically graded and correlated with a biomarker of Fabry disease (lyso-Gb3).

Results

In comparison to an age-matched control group, a significant amount of HRF was identified in macular SD-OCT images in FD patients. These HRF were localized within the inner retinal layers. Furthermore, lyso-Gb3 levels correlated significantly with the quantitative evaluation of HRF (p < 0,001). In addition, the vessel tortuosity was remarkably increased in FD patients compared to control persons and correlated significantly with lyso-G3 levels (p = 0.005). A further subanalysis revealed significantly higher HRF and vessel tortuosity scores in male patients with the classic FD phenotype.

Conclusions

The observational, cross sectional, comparative study describes novel intraretinal findings in patients with FD. We were able to identify suspicious HRF within the inner retinal layers. These findings were not accompanied by functional limitations, as visual acuity remained unchanged. However, HRF correlated well with lyso-Gb3, a degradation product of the accumulating protein Gb3 and might potentially indicate Gb3 accumulation within the highly metabolic and densely vascularized macula.

Fabry keratopathy: manifestations and changes over time

AIMS

The goal was to find if changes in Fabry keratopathy were clinically observable over time. Also observed were variations of Fabry keratopathy, supplemental features, unique presentations and differences between keratopathies of right and left corneas and the same family and genotype.

METHODS

Biomicroscopic images of Fabry keratopathy in 10 persons with classic Fabry disease, 5 men and 5 women, were captured over an 18-month period. The keratopathies were categorised and scrutinised for changes over time, and differences between corneas of the same individual, family and genotype.

RESULTS

Fabry keratopathy ranged from mild change to marked change over 18 months. There was a great variety of whorl patterns. A few keratopathies were amorphous without vortices and many vortices were supplemented with amorphous features. All keratopathies were accompanied by diffuse epithelial haze. There was a range from negligible difference to marked difference between right and left eyes of the same individuals with similarities appearing as imprecise mirror images of each other. In some corneas, prominent vertical streams from the superior limbus integrated into the primary keratopathy. Comparisons between persons with the same family and genotype were obscured by gender and differences between right and left eyes.

CONCLUSIONS

Practitioners should be better able to detect Fabry disease having a fuller understanding of the variety of presentations of the dynamic, pathognomonic Fabry keratopathy. Routes of continuous centripetal renewal of corneal epithelium are spatially unique to each eye, in some cases subsidised by direct contribution of basal cells streamed from the superior limbus.

Ocular findings in Fabry disease in Colombian patients

Fabry disease is a rare X-linked disorder caused by an alpha-galactosidase enzyme deficiency, which leads to a progressive lysosomal glycosphingolipids accumulation, mainly globotriaosylceramide, in multiple organism tissues including the eye.This case series describes the first ophthalmological Colombian report of Fabry disease highlighting the importance of ocular signs as markers of the disease, useful in diagnosis and treatment to avoid long-term complications that lead to a morbi-mortality increment.We describe five cases of Fabry disease from Bogotá, Colombia, including a complete clinical history, ophthalmologic, optometric examination, and photographs. We found that all patients had refractive defects and that in all cases corneal verticillata pattern was found. Four patients presented with posterior capsule lens brown-beige deposits and four patients had conjunctival and retinal tortuous vessels. A complete ophthalmologic examination is important for prompt diagnosis, which is key to starting a multidisciplinary treatment and reducing morbi-mortality.

Cornea verticillata in Fabry disease: a comparative study between slit-lamp examination and in vivo corneal confocal microscopy

Purpose

To compare the diagnostic power of slit-lamp examination with the in vivo corneal confocal microscopy (IVCM) as the gold standard in assessing the presence of corneal epithelial deposits in patients with Fabry disease (FD).

Methods

Fourteen patients with FD (4 males, 10 females; mean age, 46.8 years) and eight healthy controls (4 males, 4 females; mean age, 36.75 years) were included. All subjects underwent slit-lamp examination and IVCM of both central and peripheral corneal quadrants with the Heidelberg Retina Tomograph-III in combination with the Rostock Cornea Module.

Results

In patients with FD, 9 of 28 eyes (32%) showed the presence of cornea verticillata at the slit-lamp examination and 25 eyes (89%) showed the presence of epithelial hyper-reflective deposits at the IVCM. Of the 19 eyes negative at the slit-lamp examination, 16 eyes showed the presence of epithelial deposits at the IVCM. Compared with controls, patients with FD had a significantly reduced number, density and length of nerve fibres at the level of corneal sub-basal nerve plexus, but a significantly higher grade of fibres tortuosity.

Conclusions

The slit-lamp examination has a limited diagnostic power in the detection of epithelial deposits in patients with FD when compared with the IVCM. In fact, the slit-lamp examination suffers from a high number of false negative results and, consequently, from a low negative predictive value (16%). IVCM allows the detection of corneal microstructural changes in patients with FD and may represent a reliable tool for the early diagnosis and follow-up of the disease.

Longitudinal study on ocular manifestations in a cohort of patients with Fabry disease

Purpose

This study aims to assess the evolution of ocular manifestations in a cohort of Fabry patients.

Methods

This is a prospective observational study conducted from 2013 to 2017 (5 consecutive exams). All subjects underwent a comprehensive ocular examination including oriented case history, refraction, corneal topography, biomechanical corneal properties and pachometry assessments, aberrometry, anterior segment evaluation, double-frequency visual field (FDT), intra-ocular pressure, and ocular fundus. At baseline, 41 subjects enrolled but 9 dropped-out and 4 files were not kept for analysis (missing data). Remaining 28 subjects were classified into: Group 1 -hemizygotes (HMZ), all on enzyme replacement therapy (ERT) (N = 10); Group 2 -heterozygotes (HTZ) actively ERT-treated (N = 8), and Group 3 -HTZ not treated (N = 10).

Results

There is a high intra and inter-subjects variability. At baseline, prevalence of the ocular manifestations found is similar to published data: cornea verticillata (89.2%), conjunctival vessels tortuosity (85.7%), corneal haze (67.8%), retinal vessels tortuosity (64.2%), anterior cataract (39.2%) and posterior cataract (28.5%). Prevalence for new elements are found: upper lid vessels toricity (96.4%) and micro-aneurysms (42.8%). At the end, micro-aneurysms (+82%), posterior cataract (+75%) corneal haze (+21%) anterior cataract (+17%) and retinal vessels tortuosities (+4%) evolved in prevalence and severity despite the fact that 68% of the patients were on ERT. Treated heterozygotes evolved more than other groups (p>0.05).

Conclusion

ERT does not seem to halt the clinical evolution of several ocular manifestations. Longer observational time and objective grading systems may be required to fully confirm these findings.

Quantitative Analysis of Conjunctival and Retinal Vessels in Fabry Disease

Fabry Disease (FD) is a rare X-linked lysosomal storage disorder characterized by systemic and ocular involvement. It has been described an increasing in retinal and conjunctival vessel tortuosity and this feature represents an important marker for the disease. Currently, there is not an objective method to measure and quantify this parameter. We tested a new semi-automatic software measuring retinal and conjunctival vessel tortuosity from eye fundus and conjunctival digital images in a group of FD patients. We performed an observational case-control study evaluating three mathematical parameters describing tortuosity (sum of angle metric [SOAM], product of angle distance [PAD], triangular index [I2e]) obtained from fundus and conjunctival pictures of 11 FD patients and 11 age and sex-matched controls. Both eyes were considered. Mann-Whitney test was used to compare the FD group versus the control group and, within the FD group, male versus female patients. Linear regression analysis was performed to evaluate the possible association of retinal and conjunctival vessels tortuosity parameters with age and with specific markers of systemic disease's progression. The tortuosity parameters (SOAM, PAD and I2e) were significantly higher in retinal vessels and in conjunctival nasal vessels in FD patients in comparison with the controls (p=0.003, p=0.002, p=0.001 respectively for retina) (p=0.023, p=0.014, p=0.001 respectively for nasal conjunctiva). No significant association was found between retinal and conjunctival tortuosity parameters and increasing age or systemic involvement markers. Vessel tortuosity represents an important clinical manifestation in FD. A computer-assisted analysis of retinal and conjunctival vasculature demonstrated an increased vessels tortuosity in patients affected by Fabry disease. This non-invasive technique might be useful to help the diagnosis in early stages, to establish disease severity and monitor its progression.

Correlations Between Serum Cholesterol and Vascular Lesions in Fabry Disease Patients

BACKGROUND

Fabry disease is an X-linked lysosomal storage disorder and shows globotriosylceramide (Gb3) accumulation in multiple organs, resulting from a deficiency of α-galactosidase. In patients with Fabry disease, cardiovascular disease occurs at an early age. Previous studies have shown that serum levels of high-density lipoprotein-cholesterol (HDL-C) increase in this disease, yet its clinical significance for cardiovascular disease remains unclear. Methods and Results: In order to determine why the serum HDL-cholesterol is high in various cardiovascular diseases of Fabry disease patients, we evaluated the serum lipid profiles, ocular vascular lesions, and levels of serum vascular endothelial growth factor (VEGF) and intercellular adhesion molecule-1 in 69 patients with Fabry disease diagnosed by genetic examination. The serum HDL-C/total cholesterol (T-Chol) ratio was significantly high, especially in male patients (41.5±1.7%) regardless of body mass index. Ocular vascular lesions were more likely to occur in female patients with a high HDL-C/T-Chol ratio compared with most male patients. Female patients with a high HDL-C/T-Chol ratio also presented a high serum VEGF level, suggesting that vascular endothelium dysfunction and arteriosclerotic changes progress more severely than in patients with a normal HDL-C/T-Chol ratio. In most patients, enzyme replacement therapy improved serum Gb3 and lyso-Gb3 levels, but these Gb3 and lyso-Gb3 still remained higher than in healthy controls, which appears to result in continuous vascular arteriosclerotic changes.

CONCLUSIONS

We concluded that increased low-density lipoprotein-cholesterol uptake to the vascular wall caused by endothelial dysfunction is likely to contribute to the high HDL-C/T-Chol ratio observed in Fabry disease patients.

High incidence of co-existing factors significantly modifying the phenotype in patients with Fabry disease

Fabry disease results from deficiency of the lysosomal enzyme alpha-galactosidase A. The families of 11 index cases were screened by enzyme and molecular assays. Further clinical and laboratory investigations were carried out in all cases. Including 33 new patients, a total of 28 females (Age 25,82 ± 12,1 Range 8-46) and 16 males (Age 24,56 ± 15,04 Range 2-48) were investigated. Ten different disease-causing variants were found two of them being novel. One patient had co-existing familial mediteranian fever, one had celiac disease and three had rheumatological disorders. Lipoprotein (a) levels were elevated in 17,6%, homocysteine in 22,2%, total and low density cholesterol in 12% and antithrombin 3 levels were elevated in 13,3%. One patient was found to be heterozygous for prothrombin p.G20210A disease-causing variant (5,8%) and two for factor V Leiden disease-causing variant (11,7%). Anticardiolipin IgM antibody was found to be positive in 11,7%. The patients with abnormal cranial imaging were also noticed to have additional risk factors for thrombosis. This study provides the largest data about Fabry patients from Turkey and implies that co-existing risk factors unrelated to Fabry Disease have significant association with the presence of clinical symptoms in females and might cause an early and severe clinical course in males.

COMPUTER ASSISTED RETINAL VESSEL TORTUOSITY EVALUATION IN NOVEL MUTATION FABRY DISEASE: Towards New Prognostic Markers

PURPOSE

Fabry disease is a rare lysosomal storage disorder with systemic involvement. The authors report on a large Fabry family with GLA p.M187R mutation and exhaustive ophthalmologic assessment.

METHODS

Comprehensive systemic evaluation and genetic diagnosis were performed. Ophthalmologic evaluation included intraocular pressure/visual acuity measurement, refractometry, slit lamp examination, retinography, and optical coherence tomography. Three parameters quantified retinal vessel tortuosity: sum of angle metrics, product of angle distance, and triangular index. Calculations were semiautomatized using dedicated software.

RESULTS

Ten individuals (2 males and 8 females) were described. Seventy-five percent had retinal vessel tortuosity. One hundred percent had cornea verticillata. Perimacular vessels were predominantly involved. The correlation between the right and left eye tortuosity measurements was very tight. A significant correlation between retinal vessel tortuosity and systemic severity measured by general Mainz Severity Score Index (MSSI), renal MSSI, and neurological MSSI but no cardiac MSSI was observed. Right sum of angle metrics value was an independent statistical predictor of the general-MSSI score in presence of age.

CONCLUSION

p.M187R mutation causes a severe systemic and ophthalmologic phenotype, in both male and female patients. Semiautomatic assessment of retinal vessel tortuosity is an objective and reproducible tool. All three parameters of tortuosity are closely associated with Fabry severity scores. Studies of larger series are being awaited to establish the role of retinal vessel tortuosity as a noninvasive marker of disease progression.

Paediatric Fabry disease: prognostic significance of ocular changes for disease severity

Background

Ocular signs of Fabry disease can be seen in the first decade of life.

Methods

We examined the occurrence of ocular signs in 232 paediatric patients in the Fabry Outcome Survey (FOS) international registry and looked for relationships between the presence of eye findings and disease severity as measured by the FOS Mainz severity score index (FOS-MSSI).

Results

At least one ocular sign was found in 55/101 (54.5%) girls and 62/131 (47.3%) boys: cornea verticillata in 53/101 (52.5%) girls and 55/131 (42.0%) boys, vessel tortuosity in 17/98 (17.3%) girls and 32/131 (24.4%) boys, and posterior spoke-like lens opacities in 3/97 (3.1%) girls and 2/130 (1.5%) boys. Summary statistics showed higher median (range) age-adjusted FOS-MSSI total score indicating more severe disease in children with eye findings versus those without eye findings (0.5 [−11.0, 20.7] versus −2.3 [−11.1, 18.8]). At least one eye finding was observed in 59.1% of treated and 37.9% of untreated children.

Conclusions

We conclude that the presence of ocular signs, particularly cornea verticillata, correlates with more severe disease as indicated by FOS-MSSI scores in paediatric patients with Fabry disease. Ocular signs appear in roughly half of school-aged children with Fabry disease and are well-recognised as a valuable tool for diagnosis of Fabry disease in children; they also may help identify patients who are at risk for developing early severe manifestations of Fabry disease and who should be further evaluated and closely followed up.

Electronic supplementary material

The online version of this article (doi:10.1186/s12886-016-0374-2) contains supplementary material, which is available to authorized users.

Ophthalmic experience over 10 years in an observational nationwide Danish cohort of Fabry patients with access to enzyme replacement

PURPOSE

Enzyme replacement therapy (ERT) was offered from year 2001 to patients with Fabry disease. The ophthalmic experience was analysed, as part of a general 10-year status.

METHODS

A retrospective observational series comprising 39 patients (25 females, 14 males) closely followed by the endocrinologists, and with regular ophthalmic control. Time of inclusion was when the option of ERT was started, at age 11-60 years. Eye data (standard eye examination, including retinal imaging) were incomplete in five, due to death or non-attendance, and five patients had refused treatment.

RESULTS

Vision was normal throughout, except in two young males with total unilateral central retinal artery occlusion, prior to and during enzyme replacement, respectively. Cornea verticillata and conjunctival vessel ectasies were common. Tortuosity of retinal arterioles and venules was recorded in eight and 18 patients, respectively, and phlebopathy in 22, although generally without evidence of loss of vessel wall integrity. Systemic vascular lesions with or without loss of function were recorded for kidney (n = 23), heart (n = 17) and brain (n = 7), and an association was suggested between nephropathy and abnormal morphology of retinal vessels.

CONCLUSIONS

Thirteen of 32 patients on ERT showed a reduction of corneal deposits over the study period. Abnormal ocular vessel morphology was a frequent finding. In contrast to the function loss related to systemic ischaemic lesions, we found no indication of impairment of visual parameters in 37. Compared to other Fabry series, two of 39 patients with serious unilateral occlusive retinal disease may appear a high number. The presence of retinal tortuosity is discussed, possibly reflecting haemodynamic events related to vessel wall deposits, but could also be 'constitutional', as part of the Fabry inheritance.

Ocular signs correlate well with disease severity and genotype in Fabry disease

Ocular signs in Fabry disease have generally been regarded to be primarily of diagnostic value. We explored whether ocular findings, alone or in particular in combination with the α-galactosidase A gene mutation, have predictive value for disease severity. Data from the Fabry Outcome Survey (FOS), a large, global database sponsored by Shire, were selected for adult patients who had undergone ophthalmological examination. Three ocular signs were assessed: cornea verticillata, tortuous conjunctival and/or retinal vessels, and cataract. Fabry disease severity was measured using FOS Mainz Severity Score Index and modifications thereof. Ophthalmological data were available for 1203 (699 female, 504 male) adult patients with eye findings characteristic of Fabry disease in 55.1%. Cornea verticillata had a similar distribution in women (51.1%) and men (50.8%), whereas tortuous vessels and Fabry cataract were somewhat more frequent in men than in women. Patients with cornea verticillata, selected as the principal ocular sign for this study, had more severe disease (median score, 20.0) versus those without ocular signs (11.0; P<0.001). This finding could be confirmed by applying age adjusted severity scores. Moreover, the prevalence of cornea verticillata was significantly higher in patients with null (male, 76.9%; female, 64.5%) and missense (male, 79.2%; female, 67.4%) mutations versus mild missense (male, 17.1%; female, 23.1%) and the p.N215S (male, 15.0%; female, 15.6%) mutations (P<0.01). Our analyses show a correlation between the prevalence of ocular changes in Fabry disease and disease severity. Consequently, information on ocular findings and α-galactosidase A gene mutation may help assess the risk for more severe Fabry disease. These observed findings are of notable clinical importance, as Fabry disease is characterized by high clinical course variability and only weak genotype-phenotype correlation at the individual patient level. Further confirmatory studies are needed.

Computer assisted evaluation of retinal vessels tortuosity in Fabry disease

PURPOSE

Fabry Disease (FD) is a rare X-linked metabolic disorder characterized by diffuse deposition of sphingolipids in many tissues. Retinal vessel tortuosity is a common ocular manifestation in FD and may represent a useful marker for the disease. Unfortunately its clinical evaluation is poorly reproducibile and alternative means of evaluation may be of interest. We tested a new semi-automatic software measuring retinal vessel tortuosity from eye fundus digital images in a group of FD patients.

METHODS

Observational case-control study evaluating four mathematical parameters describing tortuosity (relative length, sum of angle metric [SOAM], product of angle distance [PAD], triangular index) obtained from fundus pictures of 35 FD patients and 35 age-matched controls. Only the right eye was considered in order to reduce bias. Mann-Whitney test was used to compare the FD group versus the control group, males versus females and patients with versus without clinically identified retinal vessels tortuosity in the FD group. Linear regression analysis was performed on a subgroup of patients to evaluate the possible association of retinal vessels tortuosity parameters with age and with markers of systemic disease's progression.

RESULTS

Three parameters (SOAM, PAD and triangular index) were significantly higher in FD patients in comparison with the controls (p < 0.0001, p = 0.001, p = 0.002 respectively). In the FD group the same three parameters showed higher values in hemizygous males than in heterozygous females ((p < 0.0001, p = 0.002, p < 0.0001 respectively).

CONCLUSION

A computer assisted analysis of retinal vasculature demonstrated an increased vessels tortuosity in FD patients. The technique might be useful to establish disease severity and monitor its progression.

Multidimensional analysis of clinical symptoms in patients with Fabry's disease

AIM

Fabry's disease is an X-linked inherited lysosomal storage disorder caused by the deficient activity of alpha-galactosidase A. The interrelationships between clinical symptoms in Fabry patients have not yet been fully established. Using cluster and multivariate analysis, the aim of the study was to determine the relationships among clinical symptoms and organ involvement, and predictive clinical symptoms for disease severity.

METHODS

Clinical data obtained from 108 French Fabry patients were retrospectively collected and analysed using multiple correspondence analysis and hierachical ascendant classification. Multivariate analysis was also performed to determine among clinical symptoms predictors for cardiac disease (HRT), renal involvement (KDN) and brain complication (STR).

RESULTS

The cohort comprised 41 male patients (aged 28.9 ± 11.6 years) and 67 female patients (aged 40.4 ± 15.5 years). Three main clusters of clinical symptoms could be delineated, characterising disease progression: the first cluster grouped digestive disorders (found in 30% of the patients) and exercise intolerance (32%), the second, cluster dyshidrosis (47%), acroparesthesia (67%), angiokeratoma (44%) and cornea verticillata (54%), the third, cluster grouped KDN (30%), HRT (39%) and STR (25%) and hearing loss (44%). In univariate analysis, the patient age predicted HRT and KDN, dyshidrosis predicted HRT and STR, angiokeratoma predicted KDN and cornea verticilla and hearing loss predicted KDN, HRT and STR. In multivariate analysis, hearing loss and age were independent predictors of organ complication.

CONCLUSION

Among the various interrelated clinical symptoms occurring in Fabry disease, patients with dyshidrosis and particularly hearing disorders appear to be at higher risk of organ complications.

Fabry disease in Argentina: an evaluation of patients enrolled in the Fabry Registry

AIMS

Fabry disease (FD) is an X-linked inborn error of metabolism caused by alpha-galactosidase A deficiency. The Fabry Registry is an ongoing, global observational database that compiles clinical data from patients with FD.

METHODS

Demographic and baseline clinical characteristics of Fabry Registry patients enrolled in Argentina were analysed and compared with patients enrolled in the rest of the world (ROW). Baseline clinical parameters included chronic kidney disease (CKD) stage, urine protein-to-creatinine ratio and left ventricular posterior wall thickness. Only data from untreated patients were included.

RESULTS

As of 1 October 2010, 3752 patients were enrolled in the Registry, 70 patients from Argentina and 3682 from the ROW. Argentinean male subjects were younger than Fabry Registry male subjects enrolled in ROW: mean current age 32.5 years vs. 39.0 years for men (p = 0.0257 by t-test). The current age (mean ± standard deviation) of female subjects enrolled in Argentina was not significantly different from that of female subjects enrolled in the ROW: 40.1 ± 17.28 vs. 43.2 ±17.95 years respectively (p = 0.2967). Overall, a smaller percentage of patients from Argentina received ERT compared with patients in the ROW (54% vs. 58% respectively). When evaluated by gender, more men and fewer women in Argentina received ERT compared with ROW (85% vs. 79% for men and 27% vs. 38% for women). A larger proportion of patients in ROW had severe CKD (stage 4 or 5) compared with Argentina (9.8% vs. 0%), most likely because of the older age of the ROW population.

CONCLUSIONS

The enrolment of Argentinean patients into the Fabry Registry has steadily increased, as has the inclusion of female and paediatric patients with FD. The medical community in Argentina should be aware of FD in these populations, as awareness will facilitate prompt diagnosis and initiation of treatment, thus leading to improved outcomes.

Retinal vascular tortuosity in DiGeorge syndrome complicated by solar retinopathy

PURPOSE

To report a case of vascular tortuosity associated with DiGeorge syndrome that was complicated by solar retinopathy.

METHODS

Case report and literature review.

RESULTS

A 56-year-old woman with DiGeorge syndrome with secondary schizophrenia and developmental delay presented with decreased vision that was worse in her left eye. Ocular examination revealed bilateral retinal vascular tortuosity involving both the arteries and veins. Both eyes had an abnormal foveal light reflex with a central yellowish hue, which was more pronounced in the left eye. Optical coherence tomography showed disruption of the photoreceptor inner segment-outer segment junction and retinal pigment epithelium centrally, which was also more prominent in the left eye.

CONCLUSION

DiGeorge syndrome is associated with retinal vascular tortuosity in a large percentage of patients. The patient's decreased vision is likely caused by solar retinopathy (prolonged sun gazing as a result of the secondary schizophrenia and developmental delay).

Lysosomal delivery of therapeutic enzymes in cell models of Fabry disease

The success of enzymatic replacement in Gaucher disease has stimulated development of targeted protein replacement for other lysosomal disorders, including Anderson-Fabry disease, which causes fatal cardiac, cerebrovascular and renal injury: deficiency of lysosomal α-Galactosidase A induces accumulation of glycosphingolipids. Endothelial cell storage was the primary endpoint in a clinical trial that led to market authorization. Two α-Galactosidase A preparations are licensed worldwide, but fatal outcomes persist, with storage remaining in many tissues. We compare mechanisms of uptake of α -Galactosidase A into cells relevant to Fabry disease, in order to investigate if the enzyme is targeted to the lysosomes in a mannose-6-phosphate receptor dependent fashion, as generally believed. α -Galactosidase A uptake was examined in fibroblasts, four different endothelial cell models, and hepatic cells in vitro. Uptake of europium-labeled human α -Galactosidase A was measured by time-resolved fluorescence. Ligand-specific uptake was quantified in inhibitor studies. Targeting to the lysosome was determined by precipitation and by confocal microscopy. The quantity and location of cation-independent mannose-6-phosphate receptors in the different cell models were investigated using confocal microscopy. Uptake and delivery of α -Galactosidase A to lysosomes in fibroblasts is mediated by the canonical mannose-6-phosphate receptor pathway, but in endothelial cells in vitro this mechanism does not operate. Moreover, this observation is supported by a striking paucity of expression of cation independent mannose-6-phosphate receptors on the plasma membrane of the four endothelial cell models and by little delivery of enzyme to lysosomes, when compared with fibroblasts. If these observations are confirmed in vivo, alternative mechanisms will be needed to explain the ready clearance of storage from endothelial cells in patients undergoing enzyme replacement therapy.

Fabry disease in latin america: data from the fabry registry

The purpose of these analyses was to characterize demographic and baseline clinical characteristics of Latin American patients with Fabry disease compared to that of patients in the rest of the world. Observational data reported to the Fabry Registry were obtained from untreated patients or prior to treatment with enzyme replacement therapy. As of October 1, 2010, 3,752 patients were enrolled in the Fabry Registry worldwide, including 333 patients within Latin America. Latin American patients tended to be younger than Fabry Registry patients enrolled in the rest of the world: mean current age 35.5 years versus 39.2 years for men (p < 0.05 by t-test), mean age 37.8 years versus 43.6 years for women (p < 0.05 by t-test). A smaller percentage of Latin American patients have received enzyme replacement therapy, compared to patients in the rest of the world: 67% versus 80% for men, and 19% versus 39% of women, respectively. Thirty-one percent of men and 22% of women in Latin America reported experiencing a significant cardiovascular, renal, or cerebrovascular event, at a mean age of 35 ± 12.6 years in men and 44 ± 12.3 years in women. Cardiovascular events were the most common type of initial clinical event among men and women in Latin America. The medical community in Latin America should be aware of Fabry disease as a possible cause of renal or cardiac dysfunction. Increased awareness will facilitate prompt diagnosis and initiation of treatment.

Confocal laser-scanning microscopy allows differentiation between Fabry disease and amiodarone-induced keratopathy

BACKGROUND

The aim of this work is to compare the microstructure of cornea verticillata in Fabry disease with amiodarone-induced keratopathy by means of in vivo confocal laser-scanning microscopy (CLSM).

METHODS

Ten eyes of ten patients suffering from Fabry disease, six eyes of six patients with amiodarone-induced keratopathy and eight eyes of healthy control subjects were examined by conventional slit-lamp microscopy and CLSM. One Fabry patient received amiodarone therapy. All Fabry patients were under enzyme replacement therapy with agalsidase alfa.

RESULTS

Seven out of ten Fabry patients and all patients receiving amiodarone showed typical cornea verticillata on slit-lamp examination. CLSM revealed hyper-reflective intracellular inclusions in basal epithelial cells of all Fabry patients with cornea verticillata and in one Fabry patient without slit-lamp-detectable vortex keratopathy, as well as in all eyes featuring amiodarone keratopathy. Amiodarone deposits were more reflective and of grossly different size. Seven Fabry patients and all amiodarone patients had stromal microdots. Two amiodarone patients showed amiodarone inclusions in the endothelium. The number of CLSM changes in Fabry patients did not correlate with that of slit-lamp detectable cornea verticillata.

CONCLUSIONS

While Fabry-induced cornea verticillata and amiodarone keratopathy cannot be distinguished by conventional slit-lamp microscopy, CLSM allows the differentiation between both etiologies in the majority of patients. CLSM appears to reveal corneal changes prior to the detection of cornea verticillata on slit-lamp microscopy and may thus be helpful in the early diagnosis of Fabry disease. CLSM does not allow quantitative monitoring of corneal changes in Fabry patients under enzyme-replacement therapy.

Fabry disease

Fabry disease (FD) is a progressive, X-linked inherited disorder of glycosphingolipid metabolism due to deficient or absent lysosomal α-galactosidase A activity. FD is pan-ethnic and the reported annual incidence of 1 in 100,000 may underestimate the true prevalence of the disease. Classically affected hemizygous males, with no residual α-galactosidase A activity may display all the characteristic neurological (pain), cutaneous (angiokeratoma), renal (proteinuria, kidney failure), cardiovascular (cardiomyopathy, arrhythmia), cochleo-vestibular and cerebrovascular (transient ischemic attacks, strokes) signs of the disease while heterozygous females have symptoms ranging from very mild to severe. Deficient activity of lysosomal α-galactosidase A results in progressive accumulation of globotriaosylceramide within lysosomes, believed to trigger a cascade of cellular events. Demonstration of marked α-galactosidase A deficiency is the definitive method for the diagnosis of hemizygous males. Enzyme analysis may occasionnally help to detect heterozygotes but is often inconclusive due to random X-chromosomal inactivation so that molecular testing (genotyping) of females is mandatory. In childhood, other possible causes of pain such as rheumatoid arthritis and 'growing pains' must be ruled out. In adulthood, multiple sclerosis is sometimes considered. Prenatal diagnosis, available by determination of enzyme activity or DNA testing in chorionic villi or cultured amniotic cells is, for ethical reasons, only considered in male fetuses. Pre-implantation diagnosis is possible. The existence of atypical variants and the availability of a specific therapy singularly complicate genetic counseling. A disease-specific therapeutic option - enzyme replacement therapy using recombinant human α-galactosidase A - has been recently introduced and its long term outcome is currently still being investigated. Conventional management consists of pain relief with analgesic drugs, nephroprotection (angiotensin converting enzyme inhibitors and angiotensin receptors blockers) and antiarrhythmic agents, whereas dialysis or renal transplantation are available for patients experiencing end-stage renal failure. With age, progressive damage to vital organ systems develops and at some point, organs may start to fail in functioning. End-stage renal disease and life-threatening cardiovascular or cerebrovascular complications limit life-expectancy of untreated males and females with reductions of 20 and 10 years, respectively, as compared to the general population. While there is increasing evidence that long-term enzyme therapy can halt disease progression, the importance of adjunctive therapies should be emphasized and the possibility of developing an oral therapy drives research forward into active site specific chaperones.

Enzyme assay and clinical assessment in subjects with a Chinese hotspot late-onset Fabry mutation (IVS4 + 919G→A)

Newborn screening for Fabry disease in Taiwan Chinese has revealed a high incidence of the late-onset GLA mutation IVS4 + 919G→A (∼1 in 1,500-1,600 males). We studied 94 adults with this mutation [22 men, 72 women; mean age: men 57.8 ± 6.0 (range 42-68), women 39.1 ± 14.1 years (range 19-82)]. Plasma α-galactosidase A activity assay was 10.4 ± 11.2% of normal in the men and 48.6 ± 19.5% of normal in the women. Echocardiography in 90 of the adults revealed left ventricular hypertrophy (LVH) in 19 (21%), including 14 of 21 men (67%) and 5 of 69 women (7%). Microalbuminuria, based on the urine albumin-to-creatinine ratio measured on at least two occasions, was present in 17 of 86 subjects (20%) (men: 5/20, 25%; women 12/66, 18%). At least one ocular manifestation consistent with Fabry disease was present in 41 of 52 subjects (79%) who underwent ophthalmologic examination, including 8 (15%) with conjunctival vessel tortuosity, 15 (29%) with cornea verticillata, 10 (19%) with Fabry cataract, and 34 (65%) with retinal vessel tortuosity. Among subjects over 40 years of age, men were more likely than women to have LVH [14/21 (67%) vs 5/25 (20%), p < 0.001]. Cardiovascular, renal and ocular abnormalities are highly prevalent in adult Taiwan Chinese subjects with the Fabry mutation IVS4 + 919G→A. Our findings contribute to the limited understanding of the course of this late-onset disease variant and underscore the need for close follow up in such patients.

Management of Fabry disease

A Fabry-kór a lizoszomális tárolási betegségek csoportjába tartozó, X-kromoszómához kötötten, recesszív módon öröklődő betegség, amely a globotriaozilceramid felhalmozódásához vezet a szervezet legkülönbözőbb szöveteiben. A betegség első tünetei többnyire gyermekkorban jelentkeznek, a progresszió során a betegek súlyos szervi károsodásokkal és korai halálozással számolhatnak. Elsősorban férfiak érintettek, azonban a betegség tüneteit heterozigóta nők esetében is megfigyelhetjük, de náluk a kórkép súlyossága változó, általában enyhébb lefolyású. Az enzimpótló kezelések megjelenése szükségessé tette, hogy részletes diagnosztikus és terápiás protokollt dolgozzunk ki. A jelen dolgozatban megjelenő ajánlásokat egy, a magyarországi Fabry-kóros betegek kezelésében részt vevő orvosokból, a diagnosztika területén dolgozó biológosukból és egyéb szakemberekből álló multidiszciplináris munkacsoport foglalta össze. A munkacsoport áttekintette a korábbi klinikai tanulmányokat, a publikált vizsgálatokat és a közelmúltban megjelent nemzetközi és nemzeti útmutatókat.

Ocular manifestations of Fabry disease within in a single kindred

BACKGROUND

Fabry disease is an X-linked lysosomal storage disorder that causes progressive complications within the kidneys, brain, and heart. Ocular manifestations of this disease are often present at a very young age, thereby facilitating early diagnosis, before the signs and symptoms of renal disease, stroke, or hypertrophic cardiomyopathy. Early diagnosis by the eye care provider may eventually reduce the morbidity and mortality of this disease through the institution of therapy before the development of sclerotic end organ damage. This study evaluated 23 Fabry-affected members of a single cohort for the presence of ocular signs of Fabry disease.

METHODS

Twenty-three patients of a single family were seen on a single day. Patients were given comprehensive ophthalmic examinations and completed a health and lifestyle questionnaire.

RESULTS

Eight hemizygous men (mean age, 32.3 years) and 15 heterozygous women (mean age, 26.9 years) from a single family of 43 known Fabry patients were evaluated. Corneal verticillata was present in all patients. Additional findings in the male patients included anterior capsule opacity (25% total) and Fabry cataract (12.5%). Thinning of the retinal nerve fiber layer was observed in one man whose medical history was significant for stroke. Conjunctival and/or retinal vessel tortuosity was present in the majority of patients (62.5% and 75% of hemizygotes, respectively; 40% and 13.3% heterozygotes, respectively). Additional findings in the women included anterior capsule opacity. The majority of patients (87.5% hemizygotes, 60% heterozygotes) felt Fabry disease had an impact on their quality of life.

CONCLUSIONS

All evaluated patients who had Fabry disease had corneal verticillata, which generally does not affect vision and is readily recognizable by slit lamp examination. Greater than 60% showed conjunctival and/or retinal vessel tortuosity. The eye care provider can play a crucial role in the early recognition of ocular manifestations of Fabry disease and decrease both the time to accurate diagnosis and the delay in the institution of disease-modifying therapy.

Fabry disease diagnostic guideline

A Fabry-kór a lizoszomális tárolási betegségek csoportjába tartozó, X-kromoszómához kötötten, recesszív módon öröklődő betegség, amely a globotriaosylceramid felhalmozódásához vezet a szervezet legkülönbözőbb szöveteiben. A betegség első tünetei többnyire gyermekkorban jelentkeznek, a progresszió során a betegek súlyos szervi károsodásokkal és korai halálozással számolhatnak. Elsősorban fiúk és férfiak érintettek, azonban a betegség tüneteit heterozigóta nők esetében is megfigyelhetjük, de náluk a kórkép súlyossága változó, általában enyhébb lefolyású. Az enzimpótló kezelések megjelenése szükségessé tette, hogy részletes diagnosztikus és terápiás protokollt dolgozzunk ki. A jelen dolgozatban megjelenő ajánlásokat egy, a magyarországi Fabry-betegek kezelésében aktívan részt vevő orvosokból, a diagnosztika területén dolgozó biológosukból és egyéb szakemberekből álló multidiszciplináris munkacsoport foglalta össze. A munkacsoport áttekintette a korábbi klinikai tanulmányokat, a publikált vizsgálatokat és a közelmúltban megjelent nemzetközi és nemzeti útmutatókat.

Doença de Fabry

A doença de Fabry é enfermidade de armazenamento lisossômico rara, ligada ao cromossomo-X, causada pela deficiência parcial ou completa da enzima alfagalactosidase A. O defeito resulta no acúmulo de globotriaosilceramida no endotélio vascular e tecidos viscerais, sendo a pele, o coração, os rins e o sistema nervoso central os mais afetados. As autoras realizam revisão da literatura relacionada a essa afecção e ressaltam que o reconhecimento precoce dos angioqueratomas e da hipoidrose constitui sinal-chave no diagnóstico dessa doença grave. Destacam também a necessidade de esses doentes serem avaliados por equipe multidisciplinar.

Fabry disease-often seen, rarely diagnosed

BACKGROUND

Data obtained from screened newborns and from persons at known risk for Fabry disease suggest that this condition is much more common in Germany than previously assumed. Its clinical manifestations are very diverse, and its differential diagnosis is correspondingly broad. Thus, there is often a delay before the diagnosis of Fabry disease is established.

METHODS

Selective literature search with special attention to studies of large groups of patients with respect to clinical manifestations, diagnostic evaluation, and treatment.

RESULTS

The number of patients carrying the diagnosis of Fabry disease in Germany lies far below what would be expected from published prevalence figures from other countries. Angiokeratoma, acroparesthesia, hypertrophic cardiomyopathy, impaired sweating and corneal opacification (cornea verticillata) are typical manifestations of Fabry disease; many patients also have other, nonspecific complaints, such as gastrointestinal disturbances. It has been clearly shown that women can manifest the entire range of clinical manifestations. Studies involving large groups of patients have improved our understanding of hearing impairment and tinnitus in Fabry disease. Therapeutic trials are currently in progress to determine whether enzyme substitution can delay the occurrence of life-threatening sequelae such as progressive renal failure and cerebrovascular events.

CONCLUSIONS

Fabry disease is still underdiagnosed. The average delay from the onset of symptoms to diagnosis is more than a decade. Treatment with human alpha-galactosidase A produced with genetic technology can improve most of the disease's manifestations.

Morphological analysis of corneal opacity in Shiba dog with GM1 gangliosidosis

GM1 gangliosidosis is one of the inherited metabolic lysosomal storage disorders characterized by neurological symptoms caused by beta-galactosidase deficiency and consequent accumulation of GM1 ganglioside in neuronal cells. Shiba dogs affected with GM1 gangliosidosis have been found to suffer from corneal opacity. In our morphological analysis, keratocyte enlargement was induced by abnormal intracellular accumulation of neutral carbohydrates, resulting in the loss of normal arrangement of collagen fibrils in the opaque cornea was found to be associated with the disorder. We therefore conclude that corneal opacity in this Shiba dog with GM1 gangliosidosis may be caused by neutral carbohydrate accumulation in lysosomes, swelling and dysfunction of keratocytes, and subsequent irregular arrangement of collagen fibrils in the corneal proper substance.

Fabry's disease

Fabry's disease is an X-linked lysosomal storage disorder caused by abnormalities in the GLA gene, which leads to a deficiency in alpha-galactosidase A. The consequent abnormal accumulation of glycosphingolipids results in several clinical signs and symptoms and substantial morbidity and mortality. This review covers all basic aspects of the disease such as epidemiology, pathophysiology, clinical presentation by systems, diagnosis, management, prevention, and repercussions on quality of life. With the development of enzyme replacement therapy in the past few years, early initiation of treatment is key for improvement in major affected organs with decreased cardiac mass and stabilisation of kidney function, and improvement in neuropathic pain, sweating, gastrointestinal symptoms, hearing loss, and pulmonary symptoms. However, treatment of individual symptoms in addition to enzyme replacement therapy seems to be needed for many patients, especially those who have had some degree of organ dysfunction. Additional data are needed to document long-term treatment outcomes.

The microstructure of cornea verticillata in Fabry disease and amiodarone-induced keratopathy: a confocal laser-scanning microscopy study

PURPOSE

The purpose of this study is to describe cornea verticillata in Fabry disease and in amiodarone-induced keratopathy and to compare the corneal microstructure of both types.

PATIENTS AND METHODS

Ten eyes from ten normal subjects, 28 eyes from 22 patients with Fabry disease confirmed by molecular genetic studies, and 16 eyes from 11 patients receiving amiodarone were examined by slit-lamp microscopy and in-vivo confocal laser-scanning microscopy (CLSM) with following three-dimensional reconstruction of the individual corneal layers. Five patients with Fabry disease were monitored during the course of enzyme replacement therapy (ERT).

RESULTS

Evidence of cornea verticillata was found by slit-lamp microscopy both in patients with Fabry disease and in those with amiodarone-induced keratopathy; CLSM revealed the same pattern of hyper-reflective deposits in the basal cell layer of corneal epithelium in both sets of patients. Microdot changes in the anterior stroma were more prevalent in patients receiving amiodarone but do not presuppose the simultaneous presence of cornea verticillata. The bulbar conjunctiva was found to be normal in all patients. The tarsal conjunctival epithelium contained round hyper-reflective structures, which are also encountered physiologically, but these were more common in patients with Fabry disease. In one out of the five patients examined, monitoring of corneal changes over time during ERT disclosed a regressive tendency of the deposits in the epithelial basal cell layer documented by CLSM.

CONCLUSIONS

The microstructural corneal changes typically seen in cornea verticillata in both Fabry disease and in amiodarone-induced keratopathy can be successfully visualized by confocal in-vivo microscopy at the level of the basal cell layer. By analogy, with the grading system for cornea verticillata based on slit-lamp microscopy, staging of these deposits in the basal cell layer can also be performed following in-vivo CLSM. The microdots in the anterior stroma as well as the changes observed in the tarsal conjunctiva should be regarded as having less diagnostic value because such changes may also occur in normal subjects. The utility of CLSM as a tool for monitoring ERT in Fabry disease over time needs to be confirmed in studies with larger sample sizes conducted over a longer period.