Nervous system and Fabry disease, from symptoms to diagnosis: damage evaluation and follow-up in adult patients, enzyme replacement, and support therapy

Fabry disease - what a gastroenterologist should know

Fabry disease is a rare, X-linked metabolic error caused by various mutations in the α-galactosidase A gene, which results in the accumulation of glycosphingolipids. Gastrointestinal symptoms are quite common in affected patients; therefore, it is important for gastroenterologists to keep it in mind as a differential diagnosis for especially challenging patients. The following review provides concise information on epidemiology and genetics, signs, and symptoms of the disease, focusing on the gastrointestinal (GI) tract, providing a brief overview of the diagnostic process and the available treatment, both disease specific and supportive, again with a focus on alleviation of gastrointestinal symptoms.

Clinical significance of small nerve fiber involvement in the early diagnosis and treatment of patients with Fabry disease

INTRODUCTION

Peripheral nervous system is early involved in Fabry disease (FD) and preferentially the small nerve fibers, causing the characteristic neuropathic pain crises usually beginning in childhood. Early detection of this likely underdiagnosed disease is an important approach because causal therapies are available.

METHODS

We conducted a case-series study to investigate the small nerve fiber involvement in FD and its contribution to the diagnosis of the disease but also to the timely effective therapy administration. We used specific structured scales of symptoms and signs to detect peripheral neuropathy, as well as suitable functional and structural tests to diagnose the small fiber neuropathy (SFN).

RESULTS

Twenty-seven consecutive patients (14 men, mean age 44.62 ± 10.70 years) with suspected FD were included in this study. Most of the patients presented symptoms of small nerve fiber involvement, which were accompanied by abnormal test results, fulfilling the criteria for SFN. The detection of SFN in our patients allowed the completion of the FD diagnostic criteria and thus the initiation of therapy. In five patients the SFN diagnosis determined the administration of therapy, whereas in two others it might be considered.

CONCLUSION

Our results further suggest the importance of early diagnosis of peripheral neuropathy, especially of small nerve fiber involvement, in patients with suspected FD as it contributes crucially not only to the diagnosis but also to the timely effective initiation of FD therapy.

Cerebral Vasoreactivity in a Fabry Disease Patient

BACKGROUND

Fabry disease (FD) is a rare X-linked multisystem lysosomal storage disease caused by partial or total deficiency of a-galactosidase A (GLA). A progressive involvement of the kidneys, heart, and brain arteries has been reported. Using the transcranial color-coded duplex Doppler (TCCD), we report the case of a Fabry disease (FD) patient with a reduction in the cerebrovascular reactivity of the basilar artery (BA).

METHODS

A 46-year-old male asymptomatic FD patient underwent ultrasound intracranial investigation.

CASE PRESENTATION

We report the case of a 46-year-old man affected by asymptomatic FD, who presented to our observation for episodes of vertigo. Cerebral MRI and AngioMRI were found to be normal. There was no postural hypotension observed. Otolaryngology and cardiac examinations revealed no pathological condition. A TCCD showed normal cerebral vascular reactivity (CVR) in the bilateral middle cerebral arteries (MCA), breath-holding index (BHI) was 1.3 in the right MCA (RMCA) and 1.4 in left MCA (LMCA), and BHI in the basilar artery (BA) was reduced (BHI: 0,56).

CONCLUSION

This case suggests an earlier alteration of CVR in the posterior cerebral circulation than in the anterior cerebral circulation in an asymptomatic FD patient. This alteration of CVR may be an earlier marker of FD diagnosis.

Blood Pressure Variability in Fabry Disease Patients

INTRODUCTION

Fabry disease is a rare metabolic, multisystemic, and X-linked lysosomal storage disorder. The involvement of the autonomic nervous system is well defined; however, data on the variability of the blood pressure (BP) and heart rate in Fabry disease are largely missing. In this study, we aimed to examine the circadian variations of BP and heart rate variability in Fabry disease patients.

METHODS

We recruited 31 consecutive adult (age >18 years) Fabry disease patients (16 males and 15 females) who were regularly followed up in our outpatient clinic between July 2019 and March 2020. We performed ambulatory blood pressure monitoring and echocardiography in all patients. We used standard deviation (SD), coefficient of variation (CV), and average real variability as the measures of variability. We constructed 2 control groups for propensity score matching using age, sex, and eGFR parameters in the first group and adding antihypertensive drug use to the above parameters in the second group.

RESULTS

All BP measurements were significantly lower in the FD group compared to that of the control groups, except the nighttime systolic BP. Regarding nondipping and reverse dipping statuses, FD patients and controls were similar. We found that none of the BP variability measures were higher in FD patients. Regarding heart rate variability data, both the nighttime SD and CV were significantly lower in FD patients compared to those of the controls.

CONCLUSION

A decrease in heart rate variability, rather than an increase in BP variability, might be an early marker of autonomic involvement in FD.

Long-term safety and efficacy of agalsidase beta in Japanese patients with Fabry disease: aggregate data from two post-authorization safety studies

BACKGROUND

Enzyme replacement therapy in Fabry disease has been available in Japan since 2004. Two post-authorization safety studies were conducted to evaluate agalsidase beta in Japanese patients with Fabry disease in real-world practice.

RESEARCH DESIGN AND METHODS

The Special Drug Use Investigation monitored the long-term safety and efficacy of agalsidase beta, and the Drug Use Investigation monitored safety in patients not participating in the Special Drug Use Investigation. Safety and efficacy evaluations included adverse drug reactions (ADRs), infusion-associated reactions and hypersensitivity reactions, and change in blood GL-3 level over time.

RESULTS

Of 396 patients in the aggregated data set, safety and efficacy analysis sets comprised 307 and 196 patients, respectively. ADRs occurred in 93 (30.3%) patients and serious ADRs occurred in 25 (8.1%) patients, with general disorders and administration site conditions (n=55, 17.9%), nervous system disorders (n=30, 9.8%) and skin and subcutaneous tissue disorders (n=23, 7.5%) the most common. Reductions in blood GL-3 levels occurred over the study, irrespective of age or disease phenotype.

CONCLUSIONS

Agalsidase beta demonstrated acceptable safety and tolerability, with sustained reductions in blood GL-3 levelsin Japanese patients with Fabry disease in real-world clinical practice.

CLINICAL TRIAL REGISTRATION

NCT00233870/AGAL03004 (Special Drug Use Investigation of Agalsidase beta).

Central nervous system vasculopathy caused by Fabry disease: a case report

Background

Fabry disease is rare, and the diagnosis is often delayed. Here, we describe a case of Fabry disease resulting in vasculopathy of the central nervous system. Magnetic resonance (MR) black-blood sequence (three-dimensional T1 volumetric isotropic turbo spin echo acquisition), with the unique advantage of imaging the vascular wall, facilitated a clear identification of the vasculopathy.

Case presentation

A 27-year-old man visited our hospital for the treatment of “ double vision 6d.” After a series of examinations, the patient was diagnosed with Fabry disease, which caused vasculopathy of the central nervous system. Subsequently, the patient was treated with corticosteroids and his symptoms were attenuated. Two months after the initial treatment, the initial lesion in the vascular vessel disappeared, however, a new lesion appeared. Similarly, four months after the initial treatment, although the previous lesion disappeared, a new lesion appeared.

Conclusions

This case highlights that clinicians should use MR black-blood sequence scan in a timely manner in case of young patients with migratory lesions of brain. In case of detection of a vascular lesion in combination with other systemic lesions, the possibility of Fabry disease should be considered.

MULTIPLE SCLEROSIS OR FABRY DISEASE - PROS AND CONS

SUMMARY – Fabry disease is a rare X-linked inherited lysosomal storage disease affecting multiple organ systems, presenting in the central nervous system (CNS) as white matter lesions with underlying cerebral vasculopathy and autoinflammatory changes of the choroid plexus and leptomeninges. We present a young female patient (age 36 years) admitted to our department due to visual loss on the left eye. Magnetic resonance imaging (MRI) showed demyelinating lesions in the frontal and parietal lobe, periventricularly, in mesencephalon and right cerebellar hemisphere, and left optic neuritis; MR angiography was normal. Her medical history revealed renal dysfunction, hypothyroidism, and miscarriage in the 6^th month of pregnancy due to eclampsia and Fabry disease in the family (mother). Cerebrospinal fluid analysis showed mild pleocytosis, normal blood brain barrier function and oligoclonal bands type 3. Visual evoked potentials showed prechiasmal dysfunction of the left optic nerve. Genetical testing for Fabry disease was positive (two heterozygous mutations), with decreased alpha galactosidase activity values and increased Lyso GB3 values. The patient received corticosteroid therapy (methylprednisolone) 1 g for 5 days, which led to regression of visual disturbances on the left eye. After this acute treatment, there was a question of definitive diagnosis and further treatment of the underlying cause. Considering renal dysfunction, miscarriage, arterial hypertension, positive genetic and biochemical testing for Fabry disease, as well as MRI findings showing lesions in posterior circulation, we concluded that the patient probably had Fabry disease with autoinflammatory changes in the CNS and should be treated with enzyme replacement therapy. Still, there was a question of optic neuritis on the left eye and positive oligoclonal bands favoring the diagnosis of multiple sclerosis. Therefore, further clinical and neuroradiological follow up was needed to distinguish multiple sclerosis and Fabry disease in this patient.

European expert consensus statement on therapeutic goals in Fabry disease

BACKGROUND

Fabry disease, an inherited lysosomal storage disorder, causes multi-organ pathology resulting in substantial morbidity and a reduced life expectancy. Although Fabry disease is an X-linked disorder, both genders may be affected, but generally to a lesser extent in females. The disease spectrum ranges from classic early-onset disease to non-classic later-onset phenotypes, with complications occurring in multiple organs or being confined to a single organ system depending on the stage of the disease. The impact of therapy depends upon patient- and disease-specific factors and timing of initiation.

METHODS

A European panel of experts collaborated to develop a set of organ-specific therapeutic goals for Fabry disease, based on evidence identified in a recent systematic literature review and consensus opinion.

RESULTS

A series of organ-specific treatment goals were developed. For each organ system, optimal treatment strategies accounted for inter-patient differences in disease severity, natural history, and treatment responses as well as the negative burden of therapy and the importance of multidisciplinary care. The consensus therapeutic goals and proposed patient management algorithm take into account the need for early disease-specific therapy to delay or slow the progression of disease as well as non-specific adjunctive therapies that prevent or treat the effects of organ damage on quality of life and long-term prognosis.

CONCLUSIONS

These consensus recommendations help advance Fabry disease management by considering the balance between anticipated clinical benefits and potential therapy-related challenges in order to facilitate individualized treatment, optimize patient care and improve quality of life.

Peripheral nerve involvement in Fabry's disease: Which investigations? A case series and review of the literature

BACKGROUND

Peripheral nerve system (PNS) involvement is common in Fabry's disease (FD), predominantly affecting the small nerve fibers that are difficult to investigate with conventional electrophysiological methods.

PATIENTS AND METHODS

Eighteen patients followed for Fabry's disease underwent a prospective series of electroneurophysiological explorations, including a study of the cardiac parasympathetic autonomic nervous system (ANS) and electrochemical skin conductance (ESC) tests. Data were compared with those obtained in 18 matched healthy controls.

RESULTS

All patients had at least one clinical sign suggestive of neuropathy: 16 reported an acrosyndrome and 12 had dyshidrosis. Cold hypoesthesia was found in 15 patients and heat hypoesthesia in 13. Electroneurophysiological investigations and study of the cardiac parasympathetic ANS were normal in all patients. The ESC was significantly lower in FD patients compared with controls.

CONCLUSION

PNS involvement is common in FD and should be suspected in patients exhibiting an acrosyndrome, dyshidrosis and/or cold hypoesthesia. Conventional electrophysiological investigations are normal. New techniques, such as ESC, provide early diagnosis of small fiber involvement that currently requires more sophisticated tests difficult to apply in routine practice.

[The neurological manifestations of Fabry disease. A review]

Fabry disease (Anderson-Fabry disease) is an X-linked recessive lysosomal storage disorder resulting from deficient activity of lysosomal hydrolase, alpha-galactosidase A (alpha-Gal A), which leads to progressive accumulation of globotriaosylceramide (Gb3) in various cells, predominantly endothelial and vascular smooth muscle cells, with clinical manifestations affecting major organs including the central nervous system. Manifestations of Fabry disease include progressive renal and cardiac insufficiency, neuropathic pain, stroke and cerebral disease, skin and gastrointestinal symptoms. Clinical onset usually occurs in childhood, but many severe patients are diagnosed in adulthood. Females may be severely affected as males and both may die prematurely due to stroke, heart disease and renal failure. Early recognition of symptoms, enzyme activity levels, concentration of Gb3 levels in the blood, urine and skin biopsies, as well as genetic testing (GLA gene) enable establishment of early diagnosis and therapeutic intervention with enzyme replacement therapy. Enzyme replacement therapy can stabilize or reduce the progression of the disease. Early therapy may prevent complications of the disease.

Pain management strategies for neuropathic pain in Fabry disease--a systematic review

Background

Neuropathic pain is one of the key features of (classical) Fabry disease (FD). No randomized clinical trials comparing effectiveness of different pain management strategies have been performed. This review aims to give an overview of existing pain management strategies.

Methods

PubMed and Embase were searched up to September 2014 for relevant articles on treatment of neuropathic pain in FD.

Results

Seven-hundred-thirty-one articles were identified of which 26 were included in the analysis. Studies reported on 55 individuals in total, with group-sizes ranging from 1 to 8. Carbamazepine appeared most beneficial: complete pain relief in 5/25, partial relief in 17/25, and no benefit in 3/25 patients. Phenytoin resulted in complete relief in 1/27, partial relief in 12/27 and no benefit in 6/27 patients. In 8 patients a significant reduction in the frequency of pain attacks was described. Gabapentin caused partial relief in 6/7 and no relief in 1/7 patients. Little evidence was reported for SSNRI’s or treatment combinations. Adverse-effects were reported in all treatment strategies.

Conclusions

Only for carbamazepine, phenytoin and gabapentin there is evidence of effectiveness in neuropathic pain due to FD, but comparison of effectiveness between these drugs is lacking. In routine clinical practice adverse-effects may discourage use of carbamazepine and phenytoin in favor of second-generation antiepileptic drugs, but this is currently not supported by clinical evidence. This review suffers greatly from incomplete outcome reports and a predominance of case reports, which emphasizes the need for robust clinical trials and observational cohort studies.

No Fabry Disease in Patients Presenting with Isolated Small Fiber Neuropathy

Objective

Screening for Fabry disease in patients with small fiber neuropathy has been suggested, especially since Fabry disease is potentially treatable. However, the diagnostic yield of testing for Fabry disease in isolated small fiber neuropathy patients has never been systematically investigated. Our aim is to determine the presence of Fabry disease in patients with small fiber neuropathy.

Methods

Patients referred to our institute, who met the criteria for isolated small fiber neuropathy were tested for Fabry disease by measurement of alpha-Galactosidase A activity in blood, lysosomal globotriaosylsphingosine in urine and analysis on possible GLA gene mutations.

Results

725 patients diagnosed with small fiber neuropathy were screened for Fabry disease. No skin abnormalities were seen except for redness of the hands or feet in 30.9% of the patients. Alfa-Galactosidase A activity was tested in all 725 patients and showed diminished activity in eight patients. Lysosomal globotriaosylsphingosine was examined in 509 patients and was normal in all tested individuals. Screening of GLA for mutations was performed for 440 patients, including those with diminished α-Galactosidase A activity. Thirteen patients showed a GLA gene variant. One likely pathogenic variant was found in a female patient. The diagnosis Fabry disease could not be confirmed over time in this patient. Eventually none of the patients were diagnosed with Fabry disease.

Conclusions

In patients with isolated small fiber neuropathy, and no other signs compatible with Fabry disease, the diagnostic yield of testing for Fabry disease is extremely low. Testing for Fabry disease should be considered only in cases with additional characteristics, such as childhood onset, cardiovascular disease, renal failure, or typical skin lesions.

Genetics of ischaemic stroke in young adults

Background

Stroke may be a clinical expression of several inherited disorders in humans. Recognition of the underlined genetic disorders causing stroke is important for a correct diagnosis, for genetic counselling and, even if rarely, for a correct therapeutic management. Moreover, the genetics of complex diseases such the stroke, in which multiple genes interact with environmental risk factors to increase risk, has been revolutionized by the Genome-Wide Association Study (GWAS) approach.

Scope of review

Here we review the single-gene causes of ischemic stroke, bringing the reader from the candidate gene method toward the exciting new horizons of genetic technology.

Major conclusions

The aetiological diagnosis of ischemic stroke in young adults is more complex than in the elderly. The identification of a genetic cause is important to provide appropriate counseling and to start a correct therapy, when available. The advent of GWAS technology, such as for other complex pathological conditions, has contributed enormously to the understanding of many of these genetic bases. For success large, well phenotyped case cohorts are required, and international collaborations are essential.

General significance

This review focuses on the main causes of genetically-based ischemic stroke in young adults, often classified as indeterminate, investigating also the recent findings of the GWAS, in order to improve diagnostic and therapeutic management.

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The aetiological diagnosis of stroke in young adults needs a different and more complex diagnostic work up than in older adults.

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Stroke may be a clinical expression of several inherited disorders in humans.

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The most common genetic causes of stroke are CADASIL, Fabry and mitochondrial diseases.

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Recognition of the underlined genetic disorders causing stroke is important for the correct management of the patient.

Safety and efficacy of natalizumab in Belgian multiple sclerosis patients: subgroup analysis of the natalizumab observational program

Natalizumab (Tysabri(®)) is highly efficacious in controlling disease activity in relapsing multiple sclerosis (MS) patients. As it is one of the more recent therapies for MS, there remains a need for long-term safety and efficacy data of natalizumab in a clinical practice setting. The Tysabri observational program (TOP) is an open-label, multicenter, multinational, prospective observational study, aiming to recruit up to 6,000 patients with relapsing-remitting MS from Europe, Canada and Australia. The objectives of this study are to collect long-term safety and efficacy data on disease activity and disability progression. We report here the interim results of the 563 patients included in TOP between December 2007 and 2012 from Belgium. This patient cohort was older at baseline, had longer disease duration, higher neurological impairment, and a higher baseline annualized relapse rate, when compared to patients included in the pivotal phase III AFFIRM trial. Nevertheless, the efficacy of natalizumab was comparable. The annualized relapse rate on treatment was reduced by 90.70 % (p < 0.0001) with a cumulative probability of relapse of 26.87 % at 24 months. The cumulative probabilities of sustained disability improvement and progression at 24 months were 25.68 and 9.01 %, respectively. There were no new safety concerns over the follow-up period. Two cases of progressive multifocal leukoencephalopathy were diagnosed. Our results are consistent with other observational studies in the post-marketing setting.

Outcomes of patients treated through the Canadian Fabry disease initiative

BACKGROUND

The Canadian Fabry disease initiative (CFDI) tracks outcomes of subjects with Fabry disease treated enzyme replacement therapy (ERT) given to subjects who meet evidence-based treatment guidelines and cardiovascular risk factor modification.

METHODS

We report 5 year follow-up data on 362 subjects for a composite endpoint (death, neurologic or cardiovascular events, development of end-stage renal disease or sustained increase in serum creatinine of 50% from baseline).

RESULTS

At enrollment, 86 subjects had previously received ERT (Cohort 1a) and 67 subjects were newly started (Cohort 1b) and randomized to agalsidase alfa or agalsidase beta. 209 subjects did not initially meet ERT criteria (Cohort 1c), 25 of whom met ERT criteria in follow-up and were moved to Cohort 1b (total N=178 ERT treated subjects). Use of supportive therapies such as aspirin (78%), renin-angiotensin blockade (59%), and statins (55%) was common in ERT treated subjects. In Cohort 1a, 32 subjects met the composite endpoint with 8 deaths. In Cohort 1b, 16 subjects met the composite endpoint with 1 death. Cohort 1b had fewer clinical events than Cohort 1a (p=0.039) suggesting that the treatment protocol was effective in targeting subjects at an earlier stage. 19.4% of Cohort 1b subjects on agalsidase alfa and 13.3% on agalsidase beta had a clinical event (p=0.57). 10 Cohort 1c subjects had clinical events, none of which would have been prevented by earlier use of ERT.

CONCLUSIONS

Cardiovascular risk factor modification and targeted use of ERT reduce the risk of adverse outcomes related to Fabry disease.

Cerebral hemodynamics and endothelial function in patients with Fabry disease

Background

Cerebral vasculopathy have been described in Fabry disease, in which altered cerebral blood flow, vascular remodelling or impairment of endothelial function could be involved. Our study aims to evaluate these three possibilities in a group of Fabry patients, and compare it to healthy controls.

Methods

Cerebral hemodynamics, vascular remodelling and systemic endothelial function were investigated in 10 Fabry patients and compared to data from 17 healthy controls. Transcranial Doppler was used to study blood flow velocity of intracranial arteries and cerebral vasomotor reactivity. For the study of vascular remodelling and endothelial function, intima-media thickness of common carotid arteries, flow-mediated dilation in brachial artery and serum levels of soluble VCAM-1, TNF-α, high-sensitive CRP and IL-6 were measured. Differences between groups were evaluated using appropriate tests.

Results

No relevant differences were observed in cerebral hemodynamic parameters, intima-media thickness or flow-mediated dilation. There was a trend for low serum levels of IL-6 and high serum levels of TNF-α and high-sensitive CRP in Fabry patients; plasma concentrations of soluble VCAM-1 were significantly higher in Fabry disease patients than in healthy volunteers (p = 0.02).

Conclusions

In our sample, we did not find relevant alterations of cerebral hemodynamics in Fabry disease patients. Increased levels of plasmatic endothelial biomarkers seem to be the most important feature indicative of possible vascular dysfunction in Fabry disease patients.

Fabry disease

Fabry disease results from deficient activity of the enzyme α-galactosidase A and progressive lysosomal deposition of globotriaosylceramide (GL-3) in cells throughout the body. The main neurological presentations of Fabry disease patients are painful neuropathy, hypohidrosis, and stroke. Fabry neuropathy is characterized as a length-dependent peripheral neuropathy affecting mainly the small myelinated (Aδ) fibers and unmyelinated (C) fibers. Enzyme replacement therapy (ERT) has been shown to have some positive effects on the reduction of neuropathic pain, the improvement of detection threshold for thermal sensation, and sweat function. On the contrary, the effect of ERT on the central nervous system has not been established. Early initiation of ERT before irreversible organ failure is extremely important, and alternative therapeutic approaches are currently being explored. Heterozygotes suffer from peripheral neuropathy at a higher rate than previously shown, significant multisystemic disease, and severely decreased quality of life. As well as being carriers, heterozygotes also display symptoms of Fabry disease, and should be carefully monitored and given adequate therapy.

Neurological features of Fabry disease: clinical, pathophysiological aspects and therapy

Fabry disease is a multisystem, X-linked, lysosomal storage disorder caused by a mutation in the GLA gene on chromosome Xq22 resulting in alpha-galactosidase A enzyme (α-Gal A) deficiency. Neurological manifestations other than cerebrovascular accidents include small fibre neuropathy and dysautonomic disorders, which may be the presenting clinical features in a proportion of patients. An atypical disease onset may be misdiagnosed until the emergence of a more typical clinical picture, characterized by chronic renal and cardiac failure. Thus, neurologists should consider Fabry disease in differential diagnosis and provide an appropriate diagnostic work up. This review focuses on central and peripheral nervous system involving available diagnostic tools and diagnostic work up in Fabry disease. It also covers the most recent evidence regarding enzyme replacement therapy.

Efficient uptake of recombinant α-galactosidase A produced with a gene-manipulated yeast by Fabry mice kidneys

To economically produce recombinant human α-galactosidase A (GLA) with a cell culture system that does not require bovine serum, we chose methylotrophic yeast cells with the OCH1 gene, which encodes α-1,6-mannosyltransferase, deleted and over-expressing the Mnn4p (MNN4) gene, which encodes a positive regulator of mannosylphosphate transferase, as a host cell line. The enzyme (yr-hGLA) produced with the gene-manipulated yeast cells has almost the same enzymological parameters as those of the recombinant human GLA produced with cultured human fibroblasts (agalsidase alfa), which is currently used for enzyme replacement therapy for Fabry disease. However, the basic structures of their sugar chains are quite different. yr-hGLA has a high content of phosphorylated N-glycans and is well incorporated into the kidneys, the main target organ in Fabry disease, where it cleaves the accumulated glycosphingolipids. A glycoprotein production system involving this gene-manipulated yeast cell line will be useful for the development of a new enzyme replacement therapy for Fabry disease.

Fabry disease

PURPOSE OF REVIEW

This review discusses the literature on Fabry disease mainly in the domain of neurology with special attention to recent advancement.

RECENT FINDINGS

Fabry neuropathy is known as a length-dependent peripheral neuropathy affecting mainly the small myelinated (Aδ) fibers and unmyelinated (C) fibers. Recently, concerning heterozygotes, it seems that they suffer from peripheral neuropathy at a higher rate than previously shown, significant multisystemic disease, and severely decreased quality of life. The existence of an atypical variant of Fabry disease with late-onset cerebrovascular disease (cerebrovascular variant) is now suggested, like the cardiac and renal variants of Fabry disease. Although enzyme replacement therapy (ERT) has been shown to have some positive effects on reduction of neuropathic pain, the improvement of detection threshold for thermal sensation and sweat function, the effect of ERT on the central nervous system has not been established. Gene replacement therapy, chemical chaperone therapy, and ERT using modified α-N-acetylgalactosaminidase are in progress, and induced pluripotent stem cells were generated from mouse models of Fabry disease.

SUMMARY

Heterozygotes should be carefully monitored for precise estimation and adequate therapy. Early initiation of ERT before irreversible organ failure is most important, and alternative therapeutic approaches are currently being explored.

Young woman with recurrent ischemic strokes diagnosed as Fabry disease: lessons learned from a case report

Several epidemiologic studies suggest that Fabry disease should be considered in young patients with cryptogenic stroke. We report a case of a young woman presenting with recurrent ischemic strokes who was finally diagnosed with Fabry disease after impaired kidney function had been identified. Fabry disease should be considered in unexplained cases of first or recurrent strokes in young patients disregarding the gender of the patient, especially when chronic kidney disease and/or proteinuria are present. Renal function should be closely monitored in patients with strokes and followed up after the event. In this case, intravenous thrombolysis was performed after the second ischemic event. No other case of thrombolysis for ischemic stroke in Fabry disease has been described in the literature.