Arterial remodelling in Fabry disease

AIM: The enzymatic defect in Fabry disease results in the slow systemic deposition of uncleaved glycosphingolipids in the lysosomes of vascular endothelium and smooth muscle cells, leading to ischaemic strokes, cardiomyopathy and renal failure. Whereas it is known that Fabry disease affects small blood vessels, little is known about its effects on peripheral large arteries. We therefore set out to compare parameters of arterial wall structure and function in a cohort of patients with Fabry disease and an age-matched control group. METHODS: Large artery phenotype was non-invasively investigated in 21 hemizygous patients with Fabry disease and 24 age-matched male controls. Common carotid and radial artery diameter, intima-media thickness (IMT) and distensibility were determined with high-definition echotracking systems and aplanation tonometry. RESULTS: Patients with Fabry disease had a significant twofold increase in radial artery IMT and distensibility, independent of body surface area, age and mean blood pressure. In both groups, older age at the time of examination was significantly associated with larger radial artery IMT. The relationship between age and radial IMT was 2.3-fold higher in patients with Fabry disease than in controls (p < 0.01). Carotid IMT was mildly but significantly increased in patients with Fabry disease (+18%), whereas distensibility was unchanged. CONCLUSION: This study presents evidence of a major increase in arterial wall thickness and distensibility, measurable at the site of a medium-sized artery, in a cohort of patients with classic Fabry disease.     

Increased carotid intima–media thickness in the absence of atherosclerotic plaques in an adult population with Fabry disease

Aim: Fabry disease is considered primarily as a progressive small vessel disease, with ischaemic degenerative lesions involving the kidneys, brain and heart. Macrovascular involvement in male patients includes an accelerated wall hypertrophy of the radial artery and a thickening of the intima–media of the common carotid artery. The aim of this study is to evaluate the prevalence and severity of carotid artery atherosclerosis in hemizygous and heterozygous patients with Fabry disease, compared with a matched control population.
Methods: The common carotid artery intima–media thickness (IMT) of 53 patients with Fabry disease (24 men, 29 women) was measured by high-definition ultrasonography, and the presence or absence of atherosclerotic plaques reported. Results were compared with those of 120 age-matched healthy individuals (83 men, 37 women).
Results: The common carotid artery IMT was increased to the same extent in male and female patients with Fabry disease (706±211 µm and 749±395 µm, respectively) compared with that of the control population (614±113 µm). In the Fabry population, IMT did not correlate with either systolic blood pressure or with renal function (plasma creatinine). In the control population, only systolic blood pressure was positively and significantly correlated with IMT. Atherosclerotic plaques in the common carotid artery were not observed in any patient with Fabry disease, whereas 34% of the control population had carotid artery plaques, as evidenced by focal non-homogeneous intima–media thickening greater than 1.2 mm.
Conclusion: This study presents evidence of a major increase in common carotid artery IMT, both in hemizygous and heterozygous patients with Fabry disease, in the absence of focal atherosclerotic plaques. These results suggest that the conduit arteries may be protected from atherosclerosis in Fabry disease.     

Magnetic resonance imaging changes in Fabry disease

Recognized magnetic resonance imaging (MRI) abnormalities in the brains of patients with Fabry disease include the consequences of infarction and haemorrhage, non-specific white and grey matter lesions, vascular anomalies, in particular dolicho-ectasia, and a characteristic appearance of the posterior thalamus. A preliminary analysis of MRI findings in patients registered in FOS, the Fabry Outcome Survey, indicates that most patients had abnormal scans (25/47). The commonest abnormality, in males and females, was the presence of cerebral white matter lesions, the number of which increased with patient age.
Conclusion: MRI is a valuable resource for assessing the CNS complications of Fabry disease, and their response to time and treatment.     

Fabry病研究进展

Fabry病是一种遗传代谢病,与a-半乳糖苷酶A活性下降有关.主要临床特点是发作性肢体疼痛、皮肤血管角质瘤,逐渐出现心、脑、肾等器官损害.Fabry病虽然不能治愈,但早期诊断,及时给予酶替代治疗可明显改变其预后.     

Fabry病研究进展

Fabry病是一种遗传代谢病,与a-半乳糖苷酶A活性下降有关。主要临床特点是发作性肢体疼痛、皮肤血管角质瘤,逐渐出现心、脑、肾等器官损害。Fabry病虽然不能治愈,但早期诊断,及时给予酶替代治疗可明显改变其预后。     

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.     

Fabry病研究进展

Fabry病是一种遗传代谢病,与a-半乳糖苷酶A活性下降有关.主要临床特点是发作性肢体疼痛、皮肤血管角质瘤,逐渐出现心、脑、肾等器官损害.Fabry病虽然不能治愈,但早期诊断,及时给予酶替代治疗可明显改变其预后.     

Fabry病研究进展

Fabry病是一种遗传代谢病,与a-半乳糖苷酶A活性下降有关.主要临床特点是发作性肢体疼痛、皮肤血管角质瘤,逐渐出现心、脑、肾等器官损害.Fabry病虽然不能治愈,但早期诊断,及时给予酶替代治疗可明显改变其预后.     

Genotype and phenotype in Fabry disease: analysis of the Fabry Outcome Survey

Aim: Mutations of the gene ( GLA ) encoding α-galactosidase A are implicated in Fabry disease, a progressive, X-chromosomal inherited lysosomal storage disorder. FOS – the Fabry Outcome Survey – was established as a long-term surveillance study to describe the natural course of Fabry disease and its response to enzyme replacement therapy in a large cohort of European patients. Clinical phenotype, age of onset and course of Fabry disease are very variable, even within the same family, which makes it difficult to define a genotype–phenotype relationship by analysing individual patients. The FOS database contains detailed medical information on a large cohort of patients and thus has the potential to provide important information to address this question. Methods: At the time of analysis, information on 545 patients belonging to 157 families from nine European countries had been entered into the FOS database. A GLA mutation has been reported in 365 individuals (65% and 68% of all males and females, respectively) in FOS. These data were used to analyse the relationship between genotype and phenotype in Fabry disease. Results: A highly significant positive correlation was found between the age at entry into FOS and the FOS Severity Index in male patients with GLA missense mutations ( p <0.001) as well as in those carrying other types of mutations ( p <0.001). A positive correlation was also found between the age at entry into FOS and the number of affected organs in male patients with missense mutations, irrespective of whether the change in the amino acid side chain predicted in the α-galactosidase A protein was classified as a conservative or non-conservative change.
Conclusion: The data presented here suggest that there is a correlation between genotype and clinical severity.     

Evolution of renal pathology in Fabry disease

Fabry disease is a rare lysosomal storage disorder which results from deficient activity of the enzyme α-galactosidase A. The resultant deposition and progressive accumulation of glycosphingolipids in all types of body tissue leads to severe clinical manifestations involving the heart, CNS and kidney. Renal manifestations are observed relatively early in the course of the disease, and progression to end-stage renal failure is common in hemizygous males in the third to fifth decades of life.
Renal biopsy specimens reveal evidence of diffuse intracytoplasmic glycosphingolipid accumulation, mainly affecting podocytes and epithelial cells of distal tubules, which are strikingly enlarged and vacuolated. On electron microscopy the deposits appear as typical osmiophilic inclusion bodies in the cytoplasm of all kinds of renal cells, and show a characteristic 'onion skin' or 'zebra' appearance. These pathological features are also evident in heterozygous females. Deposits occur before the development of renal impairment. As patients age, the disease progresses in cells throughout the kidney, and is associated with increasing glycosphingolipid accumulation.
Conclusion : The age-related evolution of renal pathology in Fabry disease is closely correlated with progressive intracellular deposition of glycosphingolipid and ultimately leads to end-stage renal failure.     

Inner ear function in children with Fabry disease

Aim : The prevalence of hearing loss in patients with Fabry disease is still uncertain. This paper examines hearing loss in a group of young patients with Fabry disease. Methods : A clinical ear nose and throat examination, pure-tone air and bone conduction audiometry, speech audiometry and middle ear testing (tympanometry and acoustic reflex testing) were carried out in four girls and two boys with Fabry disease (age, 7–17 years), receiving enzyme replacement therapy (ERT). Results : None of the patients complained of a hearing disorder or suffered from hearing loss. Three female patients reported tinnitus; however, this was not reported as being a problem. One boy reported tinnitus for the first time during 6 months of ERT.
Conclusion : Based on this small sample of patients, it appears that the hearing disorders associated with Fabry disease develop mainly in adulthood. Tinnitus may be an earlier symptom than previously thought in 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.     

Clinical manifestations of Fabry disease in children: data from the Fabry Outcome Survey

BACKGROUND: Fabry disease is a rare X-linked disorder caused by deficient activity of the enzyme alpha-galactosidase A. This produces progressive lysosomal accumulation of globotriaosylceramide throughout the body, leading to organ failure and premature death. AIM: Here, we present the clinical manifestations of Fabry disease in children enrolled in FOS--the Fabry Outcome Survey--a European database of the natural history of Fabry disease and the effects of enzyme replacement therapy with agalsidase alfa (Replagal). METHODS: Currently, there are 545 patients in FOS, from 11 European countries. We analysed the baseline demographic and clinical characteristics of 82 of these patients (40 boys, 42 girls) who were below 18 y of age. The median age at evaluation (defined as the median age at entry into FOS) was 12.5 and 13.2 y for boys and girls, respectively. RESULTS: The most frequent early clinical manifestations of Fabry disease were neurological (acroparaesthesiae, altered temperature sensitivity) and gastrointestinal symptoms (altered bowel habits and abdominal pain), which were documented in about 80% and 60% of patients, respectively, at the time of evaluation and subsequent entry into FOS. Tinnitus, vertigo, fatigue and angiokeratoma were present in over 40% of patients. Symptoms were noted in early childhood and occurred with similar frequency in boys and girls, although the onset of symptoms was 2-5 y later in girls than in boys. There was an approximately 3-y delay from onset of symptoms to diagnosis, and patients were frequently misdiagnosed. CONCLUSION: Although the life-threatening complications of Fabry disease, such as stroke and renal and heart failure, are not seen in children, the present analysis shows that other symptoms are common and may have an impact on quality of life.     

The right ventricle in Fabry disease

Aim: Left ventricular (LV) hypertrophy is a common feature in Fabry disease-related progressive infiltrative hypertrophic cardiomyopathy and affects both men and women, but at different ages. To date, however, little is known about the role of right ventricular (RV) function in Fabry disease. Therefore, this study aimed to investigate the extent of RV involvement in patients with Fabry disease. Methods: Echocardiographic examination of the right and left ventricle was carried out in 129 patients (80 women and 49 men) with Fabry disease. Results: RV hypertrophy was present in 46 patients (35.7%). Of these patients, 13 showed signs of severely depressed right systolic function (tricuspid annulus movement <10 mm and a prolonged RV pre-ejection period/pulmonary ejection time ratio) and six patients showed additional severe depression of parameters of diastolic function (pseudo-normal or restrictive RV filling patterns). Those patients with RV hypertrophy and severely compromised systolic and diastolic function had the highest LV masses (92±11.7 g/m^2.7).
Conclusion: RV involvement is common in Fabry disease and ultimately progresses to severe systolic and diastolic RV dysfunction. These findings might explain why patients with preserved LV function can develop clinical features such as reduced exercise capacity, organomegaly and lymphoedema.     

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.     

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。     

Elevated CNS average diffusion constant in Fabry disease

Aims : Evaluation of the average brain diffusion constant in Fabry disease. Introduction : Fabry disease is an X-linked recessive lysosomal storage disorder secondary to deficiency of α-galactosidase A and resulting in excess tissue globotriaosylceramide, particularly in cerebral blood vessels. This has been associated with cerebral hyperperfusion. Increased tissue perfusion should increase interstitial water by the Starling relationship. This hypothesis was examined by measuring the average CNS diffusion constant (D_av) in patients with Fabry disease using diffusion-weighted magnetic resonance imaging (DWI). Methods : Axial DWI was performed at b = 1000 seconds/mm² and b = 1000 seconds/mm² (TR (pulse repetition time), 10 000; TE (time to echo), 100; FOV (field of view), 22 cm; 3 mm interleaved slices; image matrix, 128 × 128; GE Signa, 1.5T). Eight healthy male volunteers (age range, 21–47 years) and 17 hemizygous patients with Fabry disease (age range, 19–49 years) were examined. Following DWI acquisition, the trace image and the diffusion distribution map were calculated. The diffusion distribution curve was then fitted by a multi-modal Gaussian curve, allowing estimation of D_av. Results : The D_av was 0.743 ±; 0.024 ±; 10^-5 cm²/second (mean ±; SD) for patients with Fabry disease and 0.726 ±; 0.014 ±; 10^-5 cm²/second for the control group. D_av was significantly increased in the patients with Fabry disease compared with the controls ( p = 0.029)
Conclusions : The elevated D_av indicates increased brain tissue water diffusivity in patients with Fabry disease, a finding consistent with increased extracellular water and increased cerebral blood flow.     

Priapism and Fabry disease: A case report

A 10-year-old boy presented with priapism of 10h duration which after unsuccessful conservative measures, was relieved by a saphenocorporeal shunt. A4-year history of intermittent vague aching of fingers and toes accompanied by lowgrade fever was reported. Fabry disease was confirmed by the lack -galactosidase acitivity in serum and leucocytes. Other characteristic features of Fabry disease were not present. The condition was also diagnosed in his 14-year-old brother and suspected in his maternal grandfather who died at the age of 49 from renal failure of unknown aetiology.