Kidney function as an underestimated factor for reduced health related quality of life in patients with Fabry disease

Background

Impairments of health related quality of life (HRQoL) are frequently observed in Fabry disease (FD) and are known to be related to neuropathic pain and cardiovascular events. This study aimed to explore the role of chronic kidney disease (CKD) in a large cohort of patients with FD.

Methods

In 96 patients (53% female; age 40 ± 12 yrs) with genetically proven FD, HRQoL was assessed by the Medical Outcomes Study (SF-36) questionnaire. All patients were naïve to enzyme replacement therapy. Three categories for kidney dysfunction were chosen, eGFR ≥/<60 ml/min/1.73 m² or need of renal replacement therapy (RRT). Minor (e.g. arrhythmia, angina pectoris, etc.) and major (e.g. myocardial infarction, coronary artery bypass, stroke or implantable cardioverter-defibrillator) vascular events as well as pain and pain therapy were considered in linear regression analyses with the dimensions of HRQoL.

Results

Ten patients (10%) had impaired kidney function and a further nine were on RRT (9.4%). Kidney function and pain emerged as the main factors associated with lower scores on the SF 36, in particular on physical components (PCS beta-coefficients for CKD −6.2, for RRT −11.8, for pain −9.1, p < 0.05, respectively), while controlling for gender, vascular event and pain-therapy. Relationships were found for mental aspects of HRQoL. Age and history of vascular events were not related to HRQoL.

Conclusion

Cardiovascular events and pain are important factors related to HRQoL, social functioning and depression. Our study highlights impaired chronic kidney disease, in particular after initiation of RRT, as a strong determinant of reduced HRQoL in FD.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2369-15-188) contains supplementary material, which is available to authorized users.

Reproducibility of manual and semi-automated late enhancement quantification in patients with Fabry disease

BACKGROUND

Late enhancement (LE) imaging is increasingly used for diagnosis of non-ischemic cardiomyopathy. However, the mostly patchy appearance of LE in this context may reduce the reproducibility of LE measurement.

PURPOSE

To report intra- and inter-observer variabilities of LE measurements in Fabry disease using manual and semi-automated quantification.

MATERIAL AND METHODS

Twenty MRI data-sets of male patients aged 44 ± 7 years were analyzed twice (interval 12 months) by one observer and additionally once by a second observer. Left ventricular (LV) parameters were determined using cine MRI. Gradient-echo LE images were analyzed by manual planimetry and by a semi-automatic prototype software. Variabilities were determined by Bland-Altman analyses and additionally intra-class correlation coefficient (ICC) values were calculated to survey intra- and inter-observer reproducibility.

RESULTS

The amount of LE was 5.2 ± 5.1 mL or 2.8 ± 2.6 % of LV mass (observer 2). LE was detected predominantly intramurally in a patchy pattern. All patients had LE restricted to the basal infero-lateral parts of the LV. The extent of LE correlated to LV mass (207 ± 70 g, P < 0.05, r = 0.6). The intra- and inter-observer variabilities were -0.6 to 1.0 mL and -0.7 to 1.6 mL, respectively (95% confidence intervals). ICC values were 0.981-0.999. The semi-automatic software allowed quantification of LE areas in all patients. The comparison of LE amount determined by semi-automatic software versus manual planimetry yielded an intra-observer variability ranging from -1.9 to 2.3 mL.

CONCLUSION

Semi-automatic planimetry of patchy LE in patients with Fabry disease is feasible. The determined intra- and inter-observer variabilities for manual and semi-automatic planimetry were in the range of 20-40% of LE amount with high ICC values.

Potential role of vitamin D deficiency on Fabry cardiomyopathy

Patients with Fabry disease frequently develop left ventricular (LV) hypertrophy and renal fibrosis. Due to heat intolerance and an inability to sweat, patients tend to avoid exposure to sunlight. We hypothesized that subsequent vitamin D deficiency may contribute to Fabry cardiomyopathy. This study investigated the vitamin D status and its association with LV mass and adverse clinical symptoms in patients with Fabry disease. 25-hydroxyvitamin D (25[OH]D) was measured in 111 patients who were genetically proven to have Fabry disease. LV mass and cardiomyopathy were assessed by magnetic resonance imaging and echocardiography. In cross-sectional analyses, associations with adverse clinical outcomes were determined by linear and binary logistic regression analyses, respectively, and were adjusted for age, sex, BMI and season. Patients had a mean age of 40 ± 13 years (42% males), and a mean 25(OH)D of 23.5 ± 11.4 ng/ml. Those with overt vitamin D deficiency (25[OH]D ≤ 15 ng/ml) had an adjusted six fold higher risk of cardiomyopathy, compared to those with sufficient 25(OH)D levels >30 ng/ml (p = 0.04). The mean LV mass was distinctively different with 170 ± 75 g in deficient, 154 ± 60 g in moderately deficient and 128 ± 58 g in vitamin D sufficient patients (p = 0.01). With increasing severity of vitamin D deficiency, the median levels of proteinuria increased, as well as the prevalences of depression, edema, cornea verticillata and the need for medical pain therapy. In conclusion, vitamin D deficiency was strongly associated with cardiomyopathy and adverse clinical symptoms in patients with Fabry disease. Whether vitamin D supplementation improves complications of Fabry disease, requires a randomized controlled trial.

Gene Mutations Versus Clinically Relevant Phenotypes

Background—

Currently, no method is available to identify α-galactosidase A (agalA) mutations determining clinically relevant Fabry disease. In our largest European Fabry cohort, we investigated whether a biomarker, specific for the defect, could stratify persons at risk.

Methods and Results—

A total of 124 individuals with agalA mutations were investigated with a comprehensive clinical workup, genetic analysis, and laboratory testing, including measurements of agalA activity and lyso-Gb3 (degradation product of the accumulating Gb3). Additionally, an extensive family screening with a clinical workup of relatives was performed. The patient population was divided into 2 samples: previously described mutations (n=72) and novel mutations (n=52). The patients with previously described mutations were subdivided into 2 groups: classical mutations, which were known to cause the classic type of Fabry disease with specific symptoms and a high risk for major events in all 3 main organs (heart, kidney, and central nervous system), and atypical mutations without the typical presentation. All patients with atypical mutations (n=17) had lower lyso-Gb3 levels than any of the patients with classical Fabry disease (n=55). A cutoff value of 2.7 ng/mL separated the 2 groups. Six out of 52 patients with novel mutations showed a lyso-Gb3 level <2.7 ng/mL. Clinical investigation, blinded to lyso-Gb3 results, revealed no classic organ involvement in these patients or their relatives. In contrast, the characterization of patients with lyso-Gb3≥2.7ng/mL suggested classical Fabry mutations in most of the patients (93%).

Conclusions—

Our data show that the biomarker lyso-Gb3 may identify the clinically relevant agalA mutations leading to Fabry disease.

Long-term outcome of enzyme-replacement therapy in advanced Fabry disease: evidence for disease progression towards serious complications

OBJECTIVE

The long-term effects of enzyme-replacement therapy (ERT) in Fabry disease are unknown. Thus, the aim of this study was to determine whether ERT in patients with advanced Fabry disease affects progression towards 'hard' clinical end-points in comparison with the natural course of the disease.

METHODS

A total of 40 patients with genetically proven Fabry disease (mean age 40 ± 9 years; n = 9 women) were treated prospectively with ERT for 6 years. In addition, 40 subjects from the Fabry Registry, matched for age, sex, chronic kidney disease stage and previous transient ischaemic attack (TIA), served as a comparison group. The main outcome was a composite of stroke, end-stage renal disease (ESRD) and death. Secondary outcomes included changes in myocardial left ventricular (LV) wall thickness and replacement fibrosis, change in glomerular filtration rate (GFR), new TIA and change in neuropathic pain.

RESULTS

During a median follow-up of 6.0 years (bottom and top quartiles: 5.1, 7.2), 15 events occurred in 13 patients (n = 7 deaths, n = 4 cases of ESRD and n = 4 strokes). Sudden death occurred (n = 6) only in patients with documented ventricular tachycardia and myocardial replacement fibrosis. The annual progression of myocardial LV fibrosis in the entire cohort was 0.6 ± 0.7%. As a result, posterior end-diastolic wall thinning was observed (baseline, 13.2 ± 2.0 mm; follow-up, 11.4 ± 2.1 mm; P < 0.01). GFR decreased by 2.3 ± 4.6 mL min(-1) per year. Three patients experienced a TIA. The major clinical symptom was neuropathic pain (n = 37), and this symptom improved in 25 patients. The event rate was not different between the ERT group and the untreated (natural history) group of the Fabry Registry.

CONCLUSION

Despite ERT, clinically meaningful events including sudden cardiac death continue to develop in patients with advanced Fabry disease.

Cross-sectional baseline analysis of electrocardiography in a large cohort of patients with untreated Fabry disease

BACKGROUND

Morphology and function of Fabry cardiomyopathy has been previously studied by echocardiography and cardiac magnetic resonance (CMR). However, the value of electrocardiography (ECG) in relation to these two techniques remains largely unknown.

METHODS

One hundred fifty genetically confirmed Fabry patients were investigated using a comprehensive clinical workup comprising 12-lead ECG, echocardiography, and CMR.

RESULTS

ECG parameters at rest [PR, P wave, QT, QTc, QT dispersion and time interval from the peak to the end of the T wave (Tpeak to Tend)] were normal in the entire cohort and did not distinguish between males and females or stages of cardiomyopathy. A significant positive correlation was found between left ventricular (LV) mass on CMR and both the QRS duration and the LV Sokolow index, with the highest values in male patients with an advanced cardiomyopathy stage. No prediction of late enhancement on CMR (a sign for replacement fibrosis) was possible by a single ECG parameter. However, the absence of ST or T alterations (in 37 of 38 patients) specifically excluded late enhancement on CMR.

CONCLUSION

Our data in a large cohort of Fabry patients, including all cardiomyopathy stages, show, in contrast to former assumptions, that ECG parameters are not suitable to stage Fabry cardiomoypathy. Most ECG parameters were normal in the complete cohort. However, the absence of ST or T alterations seems to almost exclude late enhancement on CMR in these patients.

Lyso-Gb3 Indicates that the Alpha-Galactosidase A Mutation D313Y is not Clinically Relevant for Fabry Disease

The X-chromosomal-linked lysosomal storage disorder Fabry disease can lead to life-threatening manifestations. The pathological significance of the Fabry mutation D313Y is doubted, because, in general, D313Y patients do not present clinical manifestations conformable with Fabry disease. This is in contrast to the analysis of the alpha-galactosidase A activity, which is reduced in D313Y patients. We report a comprehensive clinical, biochemical and molecular genetic analysis of two patients with a D313Y mutation. The alpha-galactosidase A activity was reduced in both patients. No Fabry symptoms or Fabry organ involvement was detected in these patients. The new biomarker lyso-Gb3, severely increased in classical Fabry patients, was determined and in both patients lyso-Gb3 was below the average of a normal population.Our data for the first time not only clinically but also biochemically supports the hypothesis that the D313Y mutation is not a classical one, but a rare variant mutation.

Interdisciplinary approach towards female patients with Fabry disease

BACKGROUND

Fabry disease (FD) is a rare X-linked lysosomal storage disorder leading to an accumulation of globotriaosylceramides in the lysosomes of various organs.

DESIGN

Being X-chromosomal-linked, most studies in the past have focused on involvement in male patients. However, it has been elucidated recently that female patients can present typical organ involvement and thus need to be treated, respectively.

CONCLUSIONS

This review wants to give a systematical overview of the typical organ involvement in female patients with FD. Moreover, therapy recommendations especially for female patients are discussed.

Cerebral blood flow in patients with Fabry disease as measured by Doppler sonography is not different from that in healthy individuals and is unaffected by treatment

OBJECTIVES

The purpose of this study was to investigate cervical and cerebral blood flow characteristics in patients with Fabry disease at baseline and under enzyme replacement therapy.

METHODS

In this case-control study we prospectively studied 68 patients with Fabry disease with extracranial and transcranial Doppler sonography. We compared extracranial and transcranial cervical and cerebral blood flow properties in all patients with Fabry disease and in subgroups of those with or without enzyme replacement therapy, male and female, and with normal or impaired renal function. Eight male patients were investigated at baseline and 1 year after initiation of enzyme replacement therapy.

RESULTS

We show that cervical and cerebral blood flow parameters in patients with Fabry disease are not different from normal values regardless of sex, renal function, or enzyme replacement therapy.

CONCLUSIONS

Cervical and cerebral blood flow measured with extracranial and transcranial Doppler sonography is not altered in patients with Fabry disease. Enzyme replacement therapy does not change blood flow characteristics.

Right ventricular involvement in patients with Fabry's disease and the effect of enzyme replacement therapy

PURPOSE

According to echocardiography reports, Fabry cardiomyopathy not only affects the left ventricle (LV) but also the right ventricle (RV). Until now no MRI studies about the effect of enzyme replacement therapy (ERT) on the RV are available. We evaluated the effect of ERT on the RV.

MATERIALS AND METHODS

In this prospective trial 14 patients with genetically proven Fabry's disease were examined using a 1.5 T MR scanner before ERT and after 13 ± 1 months of ERT. All patients underwent cardiac MR imaging and the RV/LV cardiac morphology and function were analyzed.

RESULTS

At baseline examination the values were as follows: RV mass 31 ± 6 g/m (2), end-diastolic volume (EDV) 88 ± 13 ml/m (2), end-systolic volume (ESV) 39 ± 9 ml/m (2), stroke volume (SV) 49 ± 7 ml/m (2) and ejection fraction (EF) 56 ± 5 %. The RV mass and EDV decreased significantly after 13 ± 1 months on ERT (mass 27 ± 7 g/m (2), p < 0.05, EDV 76 ± 24 ml/m (2), p < 0.05), with no significant change of ESV (33 ± 13 ml/m (2)), SV (43 ± 12 ml/m (2)) and EF (57 ± 7 %). The LV mass (102 ± 26 g/m (2) vs. 94 ± 27 g/m (2), p < 0.05), EDV (76 ± 13 ml/m (2) vs. 66 ± 22 ml/m (2), p < 0.05) and ESV (29 ± 9 ml/m (2) vs. 23 ± 9 ml/m (2), p < 0.05) decreased significantly while the EF (64 ± 7 % vs. 66 ± 5 %; p < 0.05) increased significantly.

CONCLUSION

Besides the known beneficial effect on the LV, ERT improves RV mass and EDV.

Tei index in fabry disease

BACKGROUND

Systolic and diastolic dysfunction of the left ventricle are present in patients with cardiac involvement in Fabry disease. The aim of this study was to investigate the diagnostic value of the Tei index, a marker for combined diastolic and systolic function, in patients with Fabry disease.

METHODS

A total of 66 consecutive patients with genetically confirmed Fabry disease were included in this study. Standard echocardiography, including the Tei index, and magnetic resonance imaging were performed. Patients were followed for 2.9 ± 1.9 years; 56 patients received enzyme replacement therapy, and 10 patients had natural history follow-up. Patients were subdivided into three groups: (1) those without cardiac involvement, (2) those with left ventricular (LV) hypertrophy and without late enhancement on magnetic resonance imaging, and (3) those with late enhancement on magnetic resonance imaging.

RESULTS

The Tei index was significantly higher in the groups 2 (0.56 ± 0.10) and 3 (0.60 ± 0.16) compared with patients without cardiac involvement (0.44 ± 0.10) (P < .001). All patients with Tei indexes > 0.64 showed signs of cardiomyopathy. In contrast, ejection fractions were normal in all three patient groups and therefore not useful for the detection of cardiac involvement. A significant positive correlation was observed between LV wall thickness and the Tei index in the complete patient cohort. Moreover, receiver operating characteristic analysis revealed a large area under the curve for Tei index and hypertrophy, while the area under the curve for fibrosis was small. The Tei index remained unchanged in the natural history and enzyme replacement therapy groups during follow-up.

CONCLUSIONS

In this cohort, the Tei index was of limited value to detect myocardial fibrosis and monitor enzyme replacement therapy. However, the progression of cardiomyopathy toward LV hypertrophy seems to be paralleled by global functional impairment, which can be assessed by the Tei index but not by ejection fraction. Thus, the Tei index seems to be a global parameter that can detect LV functional reduction in patients with Fabry disease.

A distinct urinary biomarker pattern characteristic of female Fabry patients that mirrors response to enzyme replacement therapy

Female patients affected by Fabry disease, an X-linked lysosomal storage disorder, exhibit a wide spectrum of symptoms, which renders diagnosis, and treatment decisions challenging. No diagnostic test, other than sequencing of the alpha-galactosidase A gene, is available and no biomarker has been proven useful to screen for the disease, predict disease course and monitor response to enzyme replacement therapy. Here, we used urine proteomic analysis based on capillary electrophoresis coupled to mass spectrometry and identified a biomarker profile in adult female Fabry patients. Urine samples were taken from 35 treatment-naïve female Fabry patients and were compared to 89 age-matched healthy controls. We found a diagnostic biomarker pattern that exhibited 88.2% sensitivity and 97.8% specificity when tested in an independent validation cohort consisting of 17 treatment-naïve Fabry patients and 45 controls. The model remained highly specific when applied to additional control patients with a variety of other renal, metabolic and cardiovascular diseases. Several of the 64 identified diagnostic biomarkers showed correlations with measures of disease severity. Notably, most biomarkers responded to enzyme replacement therapy, and 8 of 11 treated patients scored negative for Fabry disease in the diagnostic model. In conclusion, we defined a urinary biomarker model that seems to be of diagnostic use for Fabry disease in female patients and may be used to monitor response to enzyme replacement therapy.

MR-based analysis of regional cardiac function in relation to cellular integrity in Fabry disease

BACKGROUND

Fabry cardiomyopathy is characterized by left ventricular (LV) hypertrophy and regional fibrosis. Recent high-end echocardiography studies of selected LV sections suggest an interrelation between regional fibrosis, impaired function, and hypertrophy possibly changing under specific enzyme replacement therapy (ERT).

METHODS

Magnetic resonance imaging (MRI) was used for a region dependent study of cardiac function, morphology and late enhancement (LE) in 25 Fabry patients before and after 12 months of ERT in comparison to 43 healthy volunteers.

RESULTS

Fabry patients presented with LV increased wall thickness (EDWT) and reduced wall thickening (WT) with a focus on basal and midventricular regions corresponding to areas of LE. The degree of hypertrophy and hypokinesia were the highest if LE was detectable. A significant decrease of the EDWT under ERT was observed in LE negative patients accompanied by a decline of hypokinesia with regional differences.

CONCLUSIONS

Regional differences of LV hypertrophy and wall motion were detected corresponding to the distribution of myocardial fibrosis (LE). Functional impairment was closely restricted to fibrotic regions while morphologic changes slightly exceeded the areas of fibrosis. ERT resulted in regional improvements whereby absence of fibrosis was connected to a better outcome.

Prominent papillary muscles in Fabry disease: a diagnostic marker?

Fabry disease is often linked with a prominent papillary muscle. It remains unknown whether this sign could be used as a diagnostic marker to screen for Fabry patients. Standard echo was performed in 101 consecutive patients with concentric left ventricular (LV) hypertrophy (28 Fabry, 30 Friedreich, 34 isolated arterial hypertension, 9 amyloidosis) and 50 healthy controls. In addition, the areas of both papillary muscles, as well as the LV endocardial circumference, were manually traced in short axis views. A ratio of papillary muscle size to LV circumference was calculated (PM_LV_ratio). The papillary muscle area was positively correlated to LV wall thickness in this cohort (p < 0.0001; r = 0.58). In all patient subgroups, the absolute papillary muscle area was significantly enlarged and the PM_LV_ratio was significantly higher when compared with controls. However, Fabry patients showed a significantly larger absolute papillary muscle area than Friedreich and amyloidosis patients and a higher PM_LV_ratio than hypertensive and amyloidosis patients. Enlarged absolute papillary muscle area was evidenced in 21 (75%), and increased PM_LV_ratio was found in 22 (78%) of 28 Fabry patients. Combining these two parameters yields a sensitivity of 75% and specificity of 86% for diagnosing Fabry disease with LV hypertrophy. Only 10 of 73 non-Fabry patients (14%) (4 Friedreich, 1 amyloidosis, 5 hypertensive) showed an increased absolute papillary muscle area and PM_LV_ratio. In conclusion, this study confirmed the assumption that the prominent papillary muscle could be an echocardiographic marker for detection of Fabry patients with concentric LV hypertrophy.

Cardiac energy metabolism is disturbed in Fabry disease and improves with enzyme replacement therapy using recombinant human galactosidase A

AIMS

In vitro studies have shown impairment of energy metabolism in cardiac fibroblasts from Fabry patients. A recent in vivo study reported an association between cardiac energy metabolism and increased myocardial mass in Fabry patients. We therefore assessed possible disturbances of cardiac energy metabolism in Fabry patients by in vivo (31)P-MR-spectroscopy. Additionally, the effect of enzyme replacement therapy (ERT) on cardiac energetics was tested.

METHODS AND RESULTS

Twenty-three patients (41 ± 9 years; 10 females) with genetically proven Fabry disease were examined with a 1.5 T Scanner, and compared with an age-matched healthy control group. Eight patients underwent ERT and had follow-up examinations after 3 and 14 months. The high-energy phosphate molecules phosphocreatine (PCr) and adenosine triphosphate (ATP) were quantified in localized 31P-spectra by SLOOP (spectral localization with optimum point spread function). Cine- and late gadolinium enhancement (LGE) studies were also performed. When compared with healthy controls, Fabry patients demonstrated reduced PCr- (6.1 ± 1.9 vs. 8.8 ± 2.6 mmol/kg; P = 0.003) and ATP concentrations (3.9 ± 1.5 vs. 4.6 ± 1.0 mmol/kg; P = 0.048). During ERT, PCr concentrations increased (7.1 ± 1.5 mmol/kg vs. 6.1 ± 1.9; P < 0.05) and left ventricular mass decreased (215 ± 55 vs. 185 ± 45 g; P = 0.012). Disturbances in cardiac energetics were not correlated to the presence or absence of cardiac fibrosis on LGE.

CONCLUSION

Cardiac energy metabolism is disturbed in Fabry disease; this may play an important role in the pathogenesis of Fabry cardiomyopathy. Enzyme replacement therapy ameliorates energetic depression.

The right ventricle in Fabry disease: natural history and impact of enzyme replacement therapy

BACKGROUND

Storage of globotriaosylceramides is present in the left and right ventricles of patients with Fabry disease. Improvement of left ventricular morphology and function during enzyme replacement therapy (ERT) has previously been reported.

OBJECTIVES

To analyse the effects of long term ERT on right ventricular morphology and function.

METHODS

This was a prospective follow-up of 75 genetically confirmed consecutive Fabry patients for 3.1±1.8 years. According to treatment guidelines the natural history was followed in 18 patients, whereas 57 patients received ERT. Standard echocardiography, strain rate imaging for regional deformation of the right and left ventricle, and magnetic resonance tomography with late enhancement (LE) imaging for the detection of fibrosis were all performed at yearly intervals.

RESULTS

Right ventricular hypertrophy was evident in 53 patients (71%) at baseline. A significant positive correlation was found between left and right ventricular wall thickness (r=0.76; p<0.0001). LE was detected in half of the patients (n=38) in the left ventricle at baseline while no patient ever had LE of the right ventricle. Patients with LE in the left ventricle presented with the lowest right ventricular deformation properties. In contrast to the left ventricle, there was no change in right ventricular wall thickness (baseline 6.9±1.6 mm vs follow-up 6.7±1.5 mm; p=0.44) or systolic strain rate (2.2±0.7/s vs 2.1±0.8/s; p=0.31) during follow-up with ERT.

CONCLUSION

The degree of right ventricular involvement in Fabry disease is related to the left ventricular cardiomyopathy stage. ERT seems to have no direct impact on right ventricular morphology and function.

Department-related tasks and organ-targeted therapy in Fabry disease: an interdisciplinary challenge

Fabry disease is a rare X-linked storage disorder leading to an accumulation of globotriaosylceramides in all cells carrying lysosomes. As the accumulation occurs in most organs, different medical specialties are involved in the diagnostics and therapy of Fabry disease. With this review of the 3 main specialties (cardiology, nephrology, and neurology) and, in addition, the adjacent specialties (ophthalmology and dermatology), we aim to discuss the division-related responsibilities and want to suggest an organ-related additional therapy besides enzyme replacement therapy.

Scoring system for renal pathology in Fabry disease: report of the International Study Group of Fabry Nephropathy (ISGFN)

BACKGROUND

In Fabry nephropathy, alpha-galactosidase deficiency leads to accumulation of glycosphingolipids in all kidney cell types, proteinuria and progressive loss of kidney function.

METHODS

An international working group of nephrologists from 11 Fabry centres identified adult Fabry patients, and pathologists scored histologic changes on renal biopsies. A standardized scoring system was developed with a modified Delphi technique assessing 59 Fabry nephropathy cases. Each case was scored independently of clinical information by at least three pathologists with an average final score reported.

RESULTS

We assessed 35 males (mean age 36.4 years) and 24 females (43.9 years) who mostly had clinically mild Fabry nephropathy. The average serum creatinine was 1.3 mg/dl (114.9 micromol/l); estimated glomerular filtration rate was 81.7 ml/min/1.73 m(2) and urine protein to creatinine ratio was 1.08 g/g (122.0 mg/mmol). Males had greater podocyte vacuolization on light microscopy (mean score) and glycosphingolipid inclusions on semi-thin sections than females. Males also had significantly more proximal tubule, peritubular capillary and vascular intimal inclusions. Arteriolar hyalinosis was similar, but females had significantly more arterial hyalinosis. Chronic kidney disease stage correlated with arterial and glomerular sclerosis scores. Significant changes, including segmental and global sclerosis, and interstitial fibrosis were seen even in patients with stage 1-2 chronic kidney disease with minimal proteinuria.

CONCLUSIONS

The development of a standardized scoring system of both disease-specific lesions, i.e. lipid deposition related, and general lesions of progression, i.e. fibrosis and sclerosis, showed a spectrum of histologic appearances even in early clinical stage of Fabry nephropathy. These findings support the role of kidney biopsy in the baseline evaluation of Fabry nephropathy, even with mild clinical disease. The scoring system will be useful for longitudinal assessment of prognosis and responses to therapy for Fabry nephropathy.

Free breathing cardiac real-time cine MR without ECG triggering

The increasing frequency of LV functional MRI studies demands for faster methods and for more comfort for the patient. We tested, whether real-time (RT) non ECG triggered MRI allows a considerable shortening of examination time in high reproducibility. RT and standard ECG-triggered breathhold cine MRI was acquired in 9 volunteers and 21 patients. Differences between both methods were assessed by Bland-Altman analyses including variability studies. Compared to standard cine MRI, RT decreased data acquisition time by more than the factor of ten. RT produced comparable results (e.g. EF in %: +0.67 [-5.63, 6.97]) except for a slight overestimation of LV mass. Interstudy and intraobserver variability of RT cine showed a low variability. Consequently, free-breathing RT cine proved to be a reliable and suitable tool for clinical routine and may be particularly relevant in patients with sub-optimal breath-holding ability and arrhythmia.

Heart valve involvement in Fabry cardiomyopathy

Fabry disease is a rare X-linked lysosomal storage disorder leading to an accumulation of glycosphingolipids in all tissues and organs including the heart. Among the pathologies of myocardial involvement, reviews and registry data list affection of heart valves and its hemodynamic significance as predominant alterations during progression of the disease. We thought to approach this uncertainty with a systematic observational study. In a single center study, 111 patients with genetically proven Fabry disease were systematically investigated by echocardiography for abnormalities of the valves in the left (aortic and mitral valve) and right heart (pulmonary and tricuspid valve). In addition, 60 patients were followed by echocardiography for 2.7 +/- 1.5 y (range 1 to 6). Both valve stenosis and regurgitation were classified as mild, moderate or severe. Overall, no patient had severe heart valve abnormalities. The most frequent findings were mild aortic (n = 17), mitral (n = 57) and tricuspid (n = 38) valve regurgitation. Only two patients showed mild aortic valve stenosis. Moderate aortic (n = 1), mitral (n = 2) or tricuspid (n = 1) regurgitation were rarely detected. All Fabry patients in advanced stages (n = 9) had only mild mitral regurgitation and one of them had mild aortic and mitral regurgitation, moderate tricuspid regurgitation and mild aortic stenosis. Thirty patients had completely normal valve function. There was no significant change toward hemodynamic relevant heart valve abnormalities during follow-up. Mild left ventricular valve regurgitations are frequent in Fabry disease. However, these valve abnormalities are not the major limitations for the Fabry heart.

Long-term effects of enzyme replacement therapy on fabry cardiomyopathy: evidence for a better outcome with early treatment

BACKGROUND

Enzyme replacement therapy with recombinant alpha-galactosidase A reduces left ventricular hypertrophy and improves regional myocardial function in patients with Fabry disease during short-term treatment. Whether enzyme replacement therapy is effective in all stages of Fabry cardiomyopathy during long-term follow-up is unknown.

METHODS AND RESULTS

We studied 32 Fabry patients over a period of 3 years regarding disease progression and clinical outcome under enzyme replacement therapy. Regional myocardial fibrosis was assessed by magnetic resonance imaging late-enhancement technique. Echocardiographic myocardial mass was calculated with the Devereux formula, and myocardial function was quantified by ultrasonic strain-rate imaging. In addition, exercise capacity was measured by bicycle stress test. All measurements were repeated at yearly intervals. At baseline, 9 patients demonstrated at least 2 fibrotic left ventricular segments (severe myocardial fibrosis), 11 had 1 left ventricular segment affected (mild fibrosis), and 12 were without fibrosis. In patients without fibrosis, enzyme replacement therapy resulted in a significant reduction in left ventricular mass (238+/-42 g at baseline, 202+/-46 g at 3 years; P for trend <0.001), an improvement in myocardial function (systolic radial strain rate, 2.3+/-0.4 and 2.9+/-0.6 seconds(-1), respectively; P for trend=0.045), and a higher exercise capacity obtained by bicycle stress exercise (106+/-14 and 122+/-26 W, respectively; P for trend=0.014). In contrast, patients with mild or severe fibrosis showed a minor reduction in left ventricular hypertrophy and no improvement in myocardial function or exercise capacity.

CONCLUSIONS

These data suggest that treatment of Fabry cardiomyopathy with recombinant alpha-galactosidase A should best be started before myocardial fibrosis has developed to achieve long-term improvement in myocardial morphology and function and exercise capacity.

Treatment of Fabry disease with different dosing regimens of agalsidase: effects on antibody formation and GL-3

Two different enzyme preparations are used for the treatment of Fabry disease patients, agalsidase alpha (Replagal, Shire) and agalsidase beta (Fabrazyme, Genzyme). Therapeutic efficacy of both products has been variable probably due to differences in gender, severity, age and other patient characteristics. We studied the occurrence of alpha-Gal A antibodies and their effect on urinary and plasma globotriaosylceramide (GL-3), plasma chitotriosidase and clinical outcome in 52 patients after 12 months of treatment with either 0.2mg/kg agalsidase alppha (10 males, 8 females) or beta (8 males, 5 females) or 1.0mg/kg agalsidase beta (10 males, 11 females). Antibodies were detected in 18/28 male patients after 6 months. None of the females developed antibodies. Following 12 months of 0.2mg/kg treatment, urinary GL-3 decreased in antibody negative (AB-) but increased in antibody positive (AB+) patients. Treatment with 1.0mg/kg gave a reduction in urinary GL-3 in both AB- and AB+ patients. Levels of plasma GL-3 and chitotriosidase decreased in all patient groups. Twelve months of 0.2mg/kg treatment did not change renal function or left ventricular mass. Further, no change in renal function was seen following 1.0mg/kg treatment and left ventricular mass decreased in both AB- and AB+ patients. In summary, alpha-Gal A antibodies frequently develop in male Fabry disease patients and interfere with urinary GL-3 excretion. Infusion of a dose of 1.0mg/kg results in a more robust decline in GL-3, less impact, if any of antibodies, stable renal function and reduction of LVMass.

Nomen est omen. Fabry disease

A 47-year-old woman was referred with increasing dyspnoea and neuropathic pain. During echocardiography, she showed the typical signs for a Fabry cardiomyopathy: global left ventricular function was normal with an ejection fraction of 65%. She had a concentric left ventricular hypertrophy with very prominent papillary muscles. In addition, the magnetic resonance tomography showed regional late enhancement in the postero-lateral wall which is the typical location of fibrosis in Fabry patients. She suffered from a genetically proven Fabry disease, and interestingly her family name is Mrs Fabry. Thus summarized, Mrs Fabry with a confirmed Fabry disease presented with a typically Fabry cardiomyopathy.

[Cardiac involvement in Fabry's disease]

Fabry's disease is a rare X-linked lysosomal storage disorder leading to an accumulation of globotriaosylceramides in the lysosomes of all tissues. The disease is characterized by a progressive involvement of important vital organs like the kidneys, the cerebrovascular system and the heart. Within the scope of this article an overview of Fabry's cardiomyopathy, the necessary cardiac diagnostic tests and, in addition, the new concept of enzyme replacement therapy is given.

Misleading terms in Anderson-Fabry disease

BACKGROUND

Signs and symptoms of classic Fabry disease manifest itself on the skin (angiokeratoma), the nervous system (acroparaesthesia), the heart (restrictive cardiomyopathy) and a variety of other organs.

MATERIALS AND METHODS

Diagnosis of Fabry disease was confirmed by genetic tests in a cohort of 100 patients and a standardized examination programme was performed in all patients. We were puzzled when applying well-established and textbook-anchored signs and symptoms to our patients.

RESULTS

Among the 47 male and 53 female patients (mean age 41 +/- 16 years) with genetically proven disease, the Fabry-type vascular skin lesions were without hyperkeratotic aspect and keratomas were virtually absent. The peripheral neuropathic pain found in all male patients was not compatible with the wording 'acro' and 'paraesthesia', suggesting a different pathophysiological mechanism. Upon echocardiographic examination, patients mainly revealed diastolic relaxation abnormalities of the heart and only one patient had a restrictive cardiac pattern.

CONCLUSIONS

Our findings suggest that some terms used to describe signs and symptoms of Fabry disease are historically derived and do not comply with state-of-the-art examination. We propose to replace the term 'angiokeratoma' with 'angioma', the term 'acroparaesthesia' with 'neuropathic pain' and the term 'restrictive cardiomyopathy' with 'cardiac hypertrophic storage disease'. As most of the physicians are not familiar with Fabry disease, terms used in the past might prevent the correct diagnosis of a potentially treatable disease.

Females with Fabry disease frequently have major organ involvement: lessons from the Fabry Registry

Fabry disease (FD) is an X-linked lysosomal storage disease caused by alpha-galactosidase A deficiency. The Fabry Registry is a global clinical effort to collect longitudinal data on FD. In the past, most "carrier" females were usually thought to be clinically unaffected. A systematic effort has been made to enroll all FD females, regardless of symptomology. Of the 1077 enrolled females in the Registry, 69.4% had symptoms and signs of FD. The median age at symptom onset among females was 13 years, and even though 84.1% had a positive family history, the diagnosis was not made until a median age of 31 years. Twenty percent experienced major cerebrovascular, cardiac, or renal events, at a median age of 46 years. Among adult females with estimated glomerular filtration rate (eGFR) data (N=638), 62.5% had an eGFR <90 ml/min/1.73 m2 and 19.0% had eGFR <60 ml/min/1.73 m2. Proteinuria 300 mg/day was present in 39.0% of females, and 22.2% had >1 gram/day. Quality of life (QoL), as measured by the SF-36((R)) survey, was impaired at a later age than in males, but both genders experience significantly impaired QoL from the third decade of life onward. Thus, females with FD have a significant risk for major organ involvement and decreased QoL. Females should be regularly monitored for signs and symptoms of FD, and considered for enzyme replacement therapy.

Update on Fabry disease: kidney involvement, renal progression and enzyme replacement therapy

Fabry disease is an X-linked lysosomal storage disorder which is caused by a deficiency of the lysosomal enzyme alpha-galactosidase A. The lack of enzyme causes a progressive intracellular accumulation of glycosphingolipids, mainly globotriaosylceramide (GL3). Affected organs are, among others, the vascular endothelium, heart, brain and kidneys, as well as the central and peripheral nervous system. With the approval of enzyme replacement therapy (ERT) in 2001, a specific treatment approach was opened for the first time. Randomized and placebo-controlled trials have shown the safety and efficacy of ERT with improvement of clinical symptoms and microvascular endothelial cell clearance. Long-term treatment outcomes in patients with severe organ manifestations, in particular proteinuria and renal function impairment, are still critical and warrant further investigation. Besides ERT being an optimized adjunctive therapy, timely initiation of ERT is important to assure optimal medical care. Subsequent follow-up assessments should be carried out in all patients on a regular basis to evaluate treatment outcomes.

Phänotypisierung durch „genetic field work”: Ist die Datenerhebung durch Fragebögen ausreichend?

BACKGROUND AND OBJECTIVE

Genetic studies of complex diseases such as diabetes mellitus (DM) require the recruitment of patients and acquisition of patient data in a time- and cost-effective manner. An effective method to do so may be genetic field work (GFW) that recruits the relatives of index cases, these relatives then replying to appropriate questionnaires. This study investigated the validity of GFW data compared with patient interviews by a physician who had examined those persons.

METHODS

122 relatives were identified through GFW among a cohort of 35 families with DM. Questionnaires with self-reported information on past medical history, cardiovascular risk factors and life style were obtained. In a second step these famiy members were interviewed and examined by a physician in an outpatient setting.

RESULTS

Comparison of the two data sets of the 122 individuals yielded clear differences which favored interviews by a physician. The number of persons declaring themselves as having DM was significantly lower by GFW than direct examination (18 vs. 27). Diabetic nephropathy was reported by four individuals by GFW, while examination resulted in the identification of 16 cases. Body weight was also clearly too low when self-reported, so that significantly lower values were recorded for BMI in the questionnaire. Hypertension was reported by 25 vs. 54 participants. The amount of cigarettes smoked was significant lower in the GFW than in physicians' examination. But the numbers recorded for myocardial infarction, peripheral vascular disease and stroke were not significantly different.

CONCLUSION

These data show that information obtained by GFW is less accurate than that collected in interview and examination by physicians. The latter are necessary to gain valid data for accurate phenotyping, while GFW is useful in the initial recruitment of relatives.

Fabry disease: baseline medical characteristics of a cohort of 1765 males and females in the Fabry Registry

The Fabry Registry is a global observational research platform established to define outcome data on the natural and treated course of this rare disorder. Participating physicians submit structured longitudinal data to a centralized, confidential database. This report describes the baseline demographic and clinical characteristics of the first 1765 patients (54% males (16% aged < 20 years) and 46% females (13% < 20 years)) enrolled in the Fabry Registry. The median ages at symptom onset and diagnosis were 9 and 23 years (males) and 13 and 32 years (females), respectively, indicating diagnostic delays in both sexes. Frequent presenting symptoms in males included neurological pain (62%), skin signs (31%), gastroenterological symptoms (19%), renal signs (unspecified) (17%), and ophthalmological signs (11%). First symptoms in females included neurological pain (41%), gastroenterological symptoms (13%), ophthalmological (12%), and skin signs (12%). For those patients reporting renal progression, the median age at occurrence was 38 years for both sexes, but onset of cerebrovascular and cardiovascular events was later in females (median 43 and 47 years, respectively) than in males (38 and 41 years, respectively). This paper demonstrates that in spite of the considerable burden of disease in both sexes that begins to manifest in childhood or adolescence, the recognition of the underlying diagnosis is delayed by 14 years in males and 19 years in females. The Fabry Registry provides data that can increase awareness of common symptoms in all age groups, as well as insight into treated and untreated disease course, leading to improved recognition and earlier treatment, and possibly to improved outcomes for affected individuals.

Impact of enzyme replacement therapy on cardiac morphology and function and late enhancement in Fabry's cardiomyopathy

The present study evaluated the evolution of cardiac morphology, function, and late enhancement as a noninvasive marker of myocardial fibrosis, and their inter-relation during enzyme replacement therapy in patients with Fabry's disease using magnetic resonance imaging and color Doppler myocardial imaging. Late enhancement, which was present in up to 50% of patients, was associated with increased left ventricular mass, the failure of a significant regression of hypertrophy during enzyme replacement therapy, and worse segmental myocardial function. Late enhancement may predict the effect of enzyme replacement therapy on left ventricular mass and cardiac function.

Clinical benefit of enzyme replacement therapy in Fabry disease

Enzyme replacement therapy (ERT) with recombinant human alpha-galactosidase A (r-halphaGalA) enhances microvascular globotriaosylceramide clearance and improves clinical symptoms in patients with Fabry disease. We evaluated whether these effects are translated into a long-term benefit of kidney and heart function. We did a single center, prospective, open label study in 26 patients with Fabry disease (one early death, follow-up in 25 patients). r-Alpha-GalA was administered in a dosage of 1 mg/kg body weight every second week. The effect of therapy on clinical end points (death, cardiac and cerebrovascular event, renal failure), cardiac and renal function monitored by Doppler echocardiography, 99Tc-GFR, and proteinuria was investigated. After a mean treatment time of 23 +/- 8 months, nine patients experienced 12 end points, including two deaths. All end points occurred in patients with impaired renal function (n = 16; GFR 71 +/- 17 ml/min/1.73 m2). Despite ERT, renal function deteriorated to 60 +/- 23 ml/min/1.73 m2 (P = 0.04) and left ventricular posterior wall thickness (PWT) did not change (14.0 +/- 2.1 vs 13.4 +/- 2.3 mm). In contrast, patients without impairment of renal function (n = 9) had a more favorable outcome (no clinical events; GFR 115 +/- 18 vs 102 +/- 14 ml/min/1.73 m2, NS; PWT 11.7 +/- 1 and 10.7+/-0.7 mm, P = 0.04). Proteinuria remained unchanged (1.34 +/- 0.94 vs 1.01 +/- 0.97 g/day, n = 10). Patients with impaired renal function have a less favorable outcome and may develop cardiovascular and renal end points despite ERT.

Morbus Fabry of the heart

Fabry Disease is an X-linked lysosomal storage disorder leading to the accumulation of glycosphingolipids, mainly globotriaosylceramides in all tissues and solid organs of the body. The disease was described by Johannes Fabry and William Anderson coevally in 1898. Beside the involvement of the central nervous system, peripheral nerves, kidneys, skin and endovascular endothelium, the heart plays a major role in the disease. Left ventricular hypertrophy is one hallmark initially presenting with preserved ventricular function. However, with progression of the disease patients die due to heart failure. Though angina is often reported, the incidence of epicardial coronary stenosis is not a dominant feature, if at all small vessel disease can occur. In respect of arrhythmias a broad spectrum can be seen including shortened or prolonged PR-intervals, AV blocks of different degrees and sometimes malignant ventricular arrhythmias. In the past, women were considered to be carriers of the disease but hardly to develop clinical symptoms. In recent years there is evidence that female carriers may more often be affected with severe symptoms. In addition, a group of Fabry patients displaying mainly cardiac involvement were described as having a cardiac variant of the disease. This implied the hypothesis that some of those patients with unexplained myocardial hypertrophy do suffer from Fabry disease. Since 2002 enzyme replacement therapy is available and there is first evidence for its efficacy to reduce hypertrophy and increase myocardial function. If this is associated with a prognostic improvement has to be determined in future studies.