Angiokeratoma corporis diffusum--Fabry disease: historical review from the original description to the introduction of enzyme replacement therapy

This paper gives a brief historical overview of Fabry disease. First described in 1898 and called angiokeratoma corporis diffusum, a succession of observations and pioneering clinical research over the past 100 years has led to our present understanding of the disease. The major milestones during this time are described, as is the work that resulted in the successful introduction of enzyme replacement therapy.     

Fabry disease and the heart: an overview of the natural history and the effect of enzyme replacement therapy

Fabry disease is a genetic disorder caused by the deficiency of α-galactosidase A, resulting in the lysosomal accumulation of glycosphingolipids. Fabry disease may result in cardiac, cerebral and renal complications. Cardiac abnormalities in patients with Fabry disease were first described in the 1960s. In the 1990s a form of Fabry disease confined to the heart was reported; however, this variant is extremely rare and a more appropriate concept is of cardiac predominance of the disease in some patients. Up to 60% of males with classic Fabry disease have cardiac abnormalities, including left ventricular hypertrophy, valvular dysfunction and conduction abnormalities. Recent data suggest that left ventricular mass and systolic function in patients with Fabry disease improve after 12 months of enzyme replacement therapy (ERT); however, many of the patients studied are relatively young and have mild cardiac abnormalities, suggesting that more research into the efficacy of ERT in older patients is necessary.
Conclusion: Cardiac manifestations are common in patients with Fabry disease and are not confined to a 'cardiac variant' of the disease.     

Monitoring the clinical and biochemical response to enzyme replacement therapy in three children with Fabry disease

Fabry disease is an X-linked disorder of glycosphingolipid metabolism resulting from a deficiency of the lysosomal enzyme -galactosidase A. This leads to the progressive accumulation of glycosphingolipids in lysosomes of most visceral tissues and in body fluids. Following successful clinical trials in adults, two recombinant enzyme preparations of -galactosidase have recently been licensed in Europe for the treatment of Fabry disease and treatment in children has commenced. We now report the clinical findings and the levels of globotriaosylceramide in plasma and urine in three boys who have been treated with enzyme replacement therapy (agalsidase beta, Fabrazyme), 1 mg/kg for 2 years. In one boy there was a rapid improvement in all the clinical and biochemical parameters measured. This has been maintained. In the other two boys, who are siblings, there was no measurable clinical improvement after 1 year and the levels of globotriaosylceramide in plasma and urine, although lower than before treatment, were still considerably elevated. There was no evidence of blocking or neutralising antibodies so the dose of enzyme was increased to 2 mg/kg at 74 weeks of therapy. At 2 years their pain scores had improved but this was not accompanied by any reduction in the plasma or urine globotriaosylceramide levels. Conclusion:measurement of globotriaosylceramide in plasma and urine may not be the most appropriate marker to monitor the progression of treatment by enzyme replacement therapy in all patients. Certainly the subjective clinical improvement in the two brothers in this report outweighed the objective biochemical findings.Abbreviations CTH globotriasosylceramide - ERT enzyme replacement therapy - FA fatty acid - LCB sphingosine - MS/MS tandem mass spectrometry     

法布里病患儿临床特点及酶替代治疗四例初探

目的分析法布里病患儿的临床特点及使用酶替代药物治疗基本情况。方法对2014年1月至2020年7月间浙江大学医学院附属儿童医院确诊的4例法布里病患儿的临床资料、实验室检查、基因变异及治疗进行回顾性分析。临床观察其酶替代药物阿加糖酶β治疗的效果。结果 4例患儿(男2例、女2例)年龄12.4(6.0~16.8)岁,临床表现各异,其中肢端疼痛1例、少汗2例、尿崩1例,均有左心室肥厚和尿检异常,但均未发现典型皮疹及听力异常。4例患儿均结合临床症状、体征、家族史,通过α-半乳糖苷酶A酶活性、基因检测结果明确诊断。共检出3个GLA基因错义变异 c.424T>C(p.C142R)、c.335G>A(p.R112H)和c.644A>G(p.N215S)。其中前2个变异为经典型法布里病患者变异位点,后者多表现为迟发型但亦有经典型的报道。例1使用阿加糖酶β用量为每次1 mg/kg静脉泵注,每2周用药1次。患儿诉用药后疼痛强度有缓解,少汗症状得到改善。患儿在最初的2个月输注阿加糖酶β过程中未发生严重不良反应,在输注阿加糖酶β 3次后24 h尿蛋白升至1 015.6 mg,未予处理,1周后复查降至正常。结论法布里病在儿童期临床表现多样,需要多学科联合协同诊断并探讨酶替代治疗的时机,阿加糖酶β治疗患儿短期严重不良反应少见。     

Vascular complications of Fabry disease: enzyme replacement and other therapies

Fabry disease is an X-linked glycosphingolipid storage disorder resulting from deficiency of α-galactosidase A. Storage of globotriaosylceramide ultimately results in multiorgan pathology, including cerebrovascular, cardiovascular and renal disease. Vascular involvement is evident throughout the body but the mechanisms by which storage on a cellular level leads to end-organ pathology are unknown. Here the evidence for abnormal blood flow, vessel architecture and endothelial function will be reviewed and possible models of vascular pathology discussed. The effects of reversal of storage within vessels by enzyme replacement therapy (ERT) and the possibilities for intervention with additional agents will be considered.
Conclusion: The pathology of Fabry disease has an important vascular component, although the underlying pathophysiology is unclear. Preliminary evidence suggests that ERT may have beneficial effects on the vascular component of this multisystem disease.     

Natural history of the cerebrovascular complications of Fabry disease

Fabry disease is a rare, X-linked lysosomal storage disease caused by an inborn deficiency of α-galactosidase A, which results in progressive accumulation of globotriaosylceramide in a range of cells and tissues. Neurological symptoms of Fabry disease, including peripheral neuropathy and cerebrovascular events, are among the most significant clinical aspects. In this paper we present the natural history and mechanisms involved in the cerebrovascular complications of Fabry disease using data reported in FOS – the Fabry Outcome Survey – and other registries and clinical studies. We discuss ways in which these manifestations can be modified by intervention, including both general measures for cerebrovascular disease and enzyme replacement therapy.
Conclusion: Data from FOS have provided important insights into the natural history of the cerebrovascular complications of Fabry disease. Furthermore, the database has demonstrated that significant renal or cardiac disease often co-exists with cerebrovascular disease, and may predispose patients with Fabry disease to neurological disability and stroke.     

Enzyme replacement therapy with agalsidase alfa in children with Fabry disease

AIM: To assess the effects of enzyme replacement therapy (ERT) in children with Fabry disease. METHODS: Safety and efficacy of ERT with agalsidase alfa, 0.2 mg/kg infused over 40 minutes every 2 weeks for 23 weeks, were studied in a multicentre open-label trial in nine boys and four girls. Median age at the start of the study was 11.0 years (range 3.5-18 years). RESULTS: Fifty-four adverse events were reported in 11 patients. No serious adverse events related to ERT were reported. Twelve of the 54 adverse events were considered possibly or probably related to ERT. Infusion reactions (8 mild, 3 moderate) occurred in four boys, in seven infusions. One boy developed IgG antibodies, although he continued to make good clinical progress. At the end of the study, two of the four boys and the one girl on regular pain medication at baseline had stopped taking analgesics. Brief Pain Inventory (BPI) scores decreased in most patients by week 12 and were sustained until the end of the study. This change was greater in the boys, who had higher (worse) BPI scores at baseline. Pain-related quality of life (QoL) scores also decreased during the study. Plasma globotriaosylceramide concentrations and urinary globotriaosylceramide:sphingomyelin ratios decreased after 12 and 23 weeks of therapy, particularly in the boys. Increases in sweat volume were recorded in three out of five of the boys and in one of two girls tested after 23 weeks of treatment. CONCLUSION: ERT with agalsidase alfa in children with Fabry disease is well tolerated and, in the short term, appears to decrease pain and to improve pain-related QoL.     

Effects of enzyme replacement therapy with agalsidase alfa on glomerular filtration rate in patients with Fabry disease: preliminary data

Progressive deposition of globotriaosylceramide results in severe complications involving the kidney, heart and brain in both hemizygous male and heterozygous female patients with Fabry disease. Analysis of renal data from FOS - the Fabry Outcome Survey - suggests that enzyme replacement therapy with agalsidase alfa can significantly improve renal function in patients with Fabry disease, at least in those with a mild decrease in glomerular filtration rate, and may also be able to slow down the natural decline in renal function in patients with a moderate reduction in glomerular filtration rate.
Conclusion : Initial results from the large cohort of patients within FOS indicate that treatment with agalsidase alfa has beneficial effects on kidney function in patients with Fabry disease.     

Cardiac involvement in Fabry disease

Fabry disease is a rare X-linked defect of the lysosomal enzyme α-galactosidase A. The disease is characterized by progressive intracellular accumulation of neutral glycosphingolipids. The storage occurs within various tissues and cells, including cardiocytes, the cardiac conduction system, and valvular fibrocytes. Cardiac involvement may be the sole manifestation of the disease, particularly in individuals with residual enzyme activity. In general, hemizygous men are more seriously affected than heterozygous women. The main cardiac manifestations include myocardial hypertrophy, which, in some patients, mimics hypertrophic cardiomyopathy. Conduction system involvement leads to PR shortening or, in later stages, to AV blocks. Arrhythmias presenting with variable severity also appear to be common. Valvular involvement is frequently noted but generally mild and clinically non-significant. Newly available enzyme replacement therapy has produced promising results in preventing further functional deterioration of affected organs and possibly also in reversing impaired function.
Conclusions : With the advent of effective enzyme replacement therapy, early diagnosis of Fabry disease may be crucial for patient prognosis.     

Hearing improvement in patients with Fabry disease treated with agalsidase alfa

Aim : To describe the nature and prevalence of hearing loss in Fabry disease, and its response to enzyme replacement therapy (ERT) with agalsidase alfa. Methods : Fifteen male patients with Fabry disease were enrolled in a randomized, double-blind study and received placebo ( n = 8) or ERT ( n = 7) with agalsidase alfa for 6 months. This was followed by an open-label extension of 36 months thus far. Alongside this trial, an additional eight men and two women have so far received open-label ERT for between 6 and 30 months. Pure-tone audiometry, impedance audio-metry and otoacoustic emission testing were performed at 0 (baseline), 6, 18, 30 and 42 months. Results : Nine patients (36%) had bilateral and ten (40%) had unilateral high-frequency sensorineural hearing loss (SNHL). Three (12%) had unilateral middle ear effusions with conductive losses persisting beyond 6 months. Only five patients (20%) had normal hearing. The high-frequency SNHL deteriorated over the first 6 months in both placebo and active treatment groups by a median 6.3 dB ( p < 0.0001, Wilcoxon matched-pairs). This hearing loss subsequently improved above baseline by 1.5 dB at 18 months (p = 0.07), by 5.0 dB at 30 months ( p = 0.006) and by 4.0 dB at 42 months ( p = 0.01).
Conclusion : Significant hearing loss, usually high-frequency SNHL, is a common manifestation of Fabry disease in adults. α-Galactosidase A replacement therapy with agalsidase alfa appears to reverse the hearing deterioration in these patients. This improvement, however, is gradual, suggesting the need for long-term ERT.     

Gaucher and Fabry diseases: from understanding pathophysiology to rational therapies

Over the past 40 years there has been remarkable development in our understanding of the pathophysiology of lysosomal storage disorders. This review describes the research carried out on the sphingolipid storage disorders from the first demonstration of the underlying metabolic abnormality in Gaucher disease to the development of enzyme replacement therapy for Gaucher and Fabry diseases. Initial developments in gene therapy are also described.
Conclusion : The introduction of enzyme replacement therapy has provided a lifeline for patients with Gaucher or Fabry disease. It is anticipated that future developments, including gene therapy, will provide additional therapeutic options.     

酶制剂Cerezyme治疗高雪氏病效果观察

目的　酶制剂cerezyme替代疗法治疗高雪氏病 4年小结。方法　 Cerezyme初剂量 6 0U/kg ,每 2周 1次静脉滴注 ,2年后疗效好转剂量改为 30U/kg。结果 　 1 5例用药 4年以上的患者 ,血红蛋白平均增加 2 1g/L ,1 4例血小板近 1 2月恢复正常 ;脾功能亢进得到改善 ,肝脾回缩 9.3%和 6 0 .6 % ,肝功能治疗 6个月后大多恢复正常 ;身高平均增长 2 5 6厘米 ,体重平均增加 1 4 5公斤 ,生活质量明显提高。结论　 在基因治疗尚未广泛应用之前 ,酶替代疗法仍是唯一改善症状的有效措施     

Individualized long‐term enzyme therapy for Gaucher disease type 1 in Slovenia

Background: Gaucher disease type 1 (GD1) was the first lysosomal storage disorder for which an effective enzyme replacement therapy was developed. We describe the management of eight GD1 patients in Slovenia who were diagnosed between the ages of 2 and 15 years. Methods: Patients were individually assessed to establish initial enzyme doses and monitored frequently to determine the effects of long‐term enzyme dose regimens. Outcomes up to 10 years after long‐term treatment are described by changes in the Zimran severity score index, chitotriosidase and acid phosphatase levels, and after 2001, bone parameters (DEXA bone mineral density scores and the MRI bone marrow burden score). Results: Following the initiation of enzyme therapy with individualized dose regimens (range 25–56 U/kg/14 days) and followed by a gradual reduction of doses (range 12–35 U/kg/14 days) during long‐term maintenance, disease status improved in all patients as measured by the Zimran severity score index (from a mean of 11.25 [median 11.5] before therapy to a mean of 4.12 [median 3.5] at last report). Anemia and leucopenia resolved in all patients, chitotriosidase and acid phosphatase levels decreased in all patients (and by over 75% in six patients) within 1 year of treatment. Bone marrow burden scores improved in all monitored patients and DXA scores improved in six of seven monitored patients. Conclusions: We conclude that enzyme therapy with relatively low, individualized dose regimens is well‐tolerated and effective in children and young adults with GD1 disease, who are regularly monitored for changes in disease status.     

Immunoglobulin abnormalities and effects of enzyme replacement therapy in children with Gaucher disease

Hyperimmunoglobulinemia is documented in patients with Gaucher disease of all ages. We investigated the frequency of hyperimmunoglobulinemia in 12 pediatric patients with type I and III Gaucher disease and the effects of enzyme replacement therapy on these abnormalities. The incidence of hyperimmunoglobulinemia was 77%, 66%, and 60% at the diagnosis, before and after ERT, respectively. Immunoglobulin G abnormalities were the most commonly seen isotype abnormality. After enzyme replacement therapy normalization of IgA and IgM levels were recorded but decline in IgG levels was less likely to occur. This study indicated the higher frequency of hyperimmunoglobulinemia in pediatric Gaucher patients.     

Improvement of bone disease with increased dose of glucocerebrosidase in a Gaucher disease patient who had a bone lesion presenting during low-dose enzyme replacement therapy

In recent years, enzyme replacement therapy has been shown to be useful for the treatment of Gaucher disease. A 10 year old Japanese boy with Gaucher disease underwent splenectomy at the age of 5 years and received enzyme replacement therapy from the age of 6 years. He had avascular necrosis of the bilateral femoral heads, which was not seen at the beginning of the therapy, without deterioration of hematological variables during maintenance therapy. The enzyme dosage was increased from 20 to 120 IU/kg per month resulting in an improvement of the clinical symptoms and bone lesion. In enzyme replacement therapy, dose increase is considered to be essential for improvement in bone disease; however, it is important to watch for the development of bone lesion.     

Neurological features in Gaucher's disease during enzyme replacement therapy

This report describes two patients with Gaucher's disease who had unusual clinical symptoms during enzyme replacement therapy. One patient was a female with type 3 Gaucher's disease. She developed a pericardial effusion at 7 y of age, which contained many Gaucher cells despite enzyme replacement therapy. She died from neurological deterioration during enzyme replacement therapy, despite an improvement in her visceral manifestations. The other patient is a male with type 2 Gaucher's disease, who has achieved long-term survival after being supported by mechanical ventilation and enzyme replacement therapy. While on enzyme replacement therapy at the age of 4 y, he suffered a generalized cutaneous disease which was clinically diagnosed as ichthyosis. Conclusion: These cases suggest that ordinary enzyme replacement therapy is insufficient for some of the non-neurological manifestations of severe types of Gaucher's disease.     

Pathophysiology and assessment of neuropathic pain in Fabry disease

Severe neuropathic pain and hypohidrosis are important symptoms of Fabry disease, particularly in the first three decades of life. The pain is associated with a length-dependent small-fibre neuropathy that also causes a selective deficiency of cold perception. Cold exposure often accentuates the pain and worsens thermal perception. The hypohidrosis leads to poor exercise and heat tolerance. The mechanisms by which α-galactosidase A deficiency causes these physiological abnormalities are poorly understood. The stored glycolipid (globotriaosylceramide) may interfere with the function of cellular membrane proteins, such as ion channels, or may lead to cytotoxicity. The characteristic neuropathic pain can be symptomatically treated with various types of anticonvulsant drugs, such as carbamazepine. Improvement in neuropathic pain as a primary outcome measure has been useful in demonstrating that enzyme replacement therapy is effective in improving pain-related quality of life in Fabry disease.
Conclusions : The dysfunction of the peripheral nervous system is easily assessable and more readily reversible with specific therapy than the destructive processes that occur in organs such as the kidney. In future, therefore, it is likely that neuropathic pain, quantitative sensory testing and hypohidrosis will serve as clinical outcome measures for studies of specific and effective therapies for Fabry disease.     

Safety of agalsidase alfa in patients with Fabry disease under 7 years

Aim: To evaluate the safety and explore the efficacy of enzyme replacement therapy (ERT) for Fabry disease with agalsidase alfa in young children enrolled in the Fabry Outcome Survey (FOS). Methods: This retrospective chart review identified eight children (mean age = 5.0 ± 1.6 [mean ± SD]) in FOS who began treatment with agalsidase alfa (0.2 mg/kg, i.v., every other week) when <7 years old. Vital signs and adverse events were monitored throughout the study period. Glomerular filtration rate (GFR) was estimated, and left ventricular mass indexed to height^2.7 (LVMi) was assessed with echocardiography. Patients received 1.2–6.7 years of treatment (mean = 4.2 years). Results: Infusion reactions occurred in three patients and were of mild or moderate severity. IgG antibodies to agalsidase alfa were found in one patient who experienced two mild and one moderate infusion reactions. Mean GFR was within the normal range at baseline and remained normal. LVMi was above the 75th percentile of age‐matched children in 5 of 6 patients evaluated at baseline. Only two patients exceeded this threshold at their last assessment. Conclusion: Long‐term observation will be needed to determine whether early initiation of ERT will prevent major organ dysfunction in these patients.