Fabry disease in Spain: description of Spanish patients and a comparison with other European countries using data from the Fabry Outcome Survey (FOS)

Time to diagnosis and determinants of diagnostic delays of people living with a rare disease: results of a Rare Barometer retrospective patient survey

Timely diagnosis is one of the most serious challenges faced by people living with a rare disease (PLWRD), and this study estimates that in Europe, the average total diagnosis time (TDT) is close to 5 years. We investigated the duration of the TDT for PLWRD in Europe, the difficulties associated with their diagnosis odyssey and the main determinants of diagnosis delays for all rare diseases (RD). We conducted a survey of PLWRD and their families using Rare Barometer, the survey initiative of EURORDIS-Rare Diseases Europe. In geographical Europe, we surveyed 6507 people living with 1675 RD in 41 countries. We then performed a descriptive analysis and ordinal logistic regressions to identify the main determinants of diagnosis delays. Average TDT is 4.7 years. 56% of respondents were diagnosed more than 6 months after a first medical contact. The main determinants of diagnosis delays are symptom onset before 30 years of age, especially during childhood (OR = 3.11; 95% CI: 2.4-4.0) and adolescence (OR = 4.79; 95% CI: 3.7-6.2), being a woman (OR = 1.22; 95% CI:1.1-1.4), living in Northern Europe (OR = 2.15; 95% CI:1.8-2.6) or Western Europe (OR = 1.96; 95% CI:1.6-2.3), the number of healthcare professionals consulted (OR = 5.15; 95% CI:4.1-6.4), misdiagnosis (OR = 2.48; 95% CI:2.1-2.9), referral to a centre of expertise (OR = 1.17; 95% CI:1.0-1.3), unmet needs for psychological support (OR = 1.34; 95% CI:1.2-1.5) and financial support (OR = 1.16; 95% CI:1.0-1.3), having a genetic disease (OR = 1.33; 95% CI:1.1-1.5) and a family history of an RD (OR = 1.36; 95% CI:1.1-1.6). These determinants can inform policies and actions to improve access to diagnosis for all PLWRD.

Diet and Physical Activity in Fabry Disease: A Narrative Review

Fabry disease (FD) is caused by mutations in the galactosidase alpha (GLA) gene which lead to the accumulation of globotriaosylceramide (Gb-3). Enzyme replacement therapy (ERT) and oral chaperone therapy are the current pharmacological treatments for this condition. However, in the literature, there is a growing emphasis on exploring non-pharmacological therapeutic strategies to improve the quality of life of patients with FD. In particular, the nutritional approach to FD has been marginally addressed in the scientific literature, although specific dietary interventions may be useful for the management of nephropathy and gastrointestinal complications, which are often present in patients with FD. Especially in cases of confirmed diagnosis of irritable bowel syndrome (IBS), a low-FODMAP diet can represent an effective approach to improving intestinal manifestations. Furthermore, it is known that some food components, such as polyphenols, may be able to modulate some pathogenetic mechanisms underlying the disease, such as inflammation and oxidative stress. Therefore, the use of healthy dietary patterns should be encouraged in this patient group. Sports practice can be useful for patients with multi-organ involvement, particularly in cardiovascular, renal, and neurological aspects. Therefore, the aim of this review is to summarize current knowledge on the role of nutrition and physical activity in FD patients.

Thiol/disulfide homeostasis as a new oxidative stress marker in patients with Fabry disease

This is the first study to show both dynamic thiol-disulfide balance and oxidative stress levels in patients with Fabry disease (FD). This prospective study consists of 30 FD patients and 30 healthy controls. Thiol and disulfide values of the study groups were evaluated using a new, cost-effective and fully automatic colorimetric method. A total of 60 subjects were included in the study. A statistically significant difference was found between the patient and control groups for native and total thiol levels (p < 0.001). In addition, disulfide levels were significantly higher in FD patients compared with the control group (p < 0.003). Native thiol levels showed significantly negative correlation with lysosomal globotriaosylceramide, total oxidant status (TOS), and oxidative stress index (OSI) levels. In addition, a positive correlation was found between disulfide/natural thiol and disulfide/total thiol ratios and TOS, OSI, and blood urea nitrogen. We found total antioxidant status levels were lower in the patient group compared to the control group, while TOS and OSI levels were higher and were statistically significant. This study highlights for the first time a novel, cost-effective and fully automated measurement of thiol-disulfide levels in patients with FD. Determination of thiol levels can make important contributions to understand the etiopathogenesis and follow-up of the disease in FD patients.

Fabry disease and sleep disorders: a systematic review

Background

Fabry disease (FD) is an X-chromosome-linked disorder characterized by a reduced or complete absence of the enzyme α-galactosidase, resulting in the accumulation of lysosomal globotriaosylceramide. Despite the presence of these deposits in multiple organs, the problem of sleep disorders within this population has very rarely been documented.

Objective

This study aimed to investigate the types and prevalence of sleep disorders among patients with FD.

Methods

Screening of the following medical databases using key terms was performed on 10 February 2023: PubMed, Scopus, and Embase. A total of 136 records were identified. The quality assessment of the studies was conducted by using tools from the National Institutes of Health (NIH) and critical appraisal tools from the Joanna Briggs Institute (JBI).

Results

The study included nine studies on sleep disorders in patients with FD. The overall quality of the majority of these studies was assessed as either poor or fair. Among 330 patients, there was a slightly higher representation of female patients (56%). Sleep problems manifested 4-5 years after the onset of FD and sometimes even after 10-11 years. Genotypes of disease associated with sleep problems were rarely described. Within the FD population, the most commonly reported conditions were excessive daytime sleepiness (EDS) as well as obstructive and central sleep apnea (OSA, CSA). However, EDS occurred more frequently in FD patients, while the prevalence of OSA and CSA was within the ranges observed in the general population. The studies included indicated a lack of association between organ impairment by primary disease and EDS and OSA. The effectiveness of enzyme replacement therapy (ERT) in treating sleep disorders was not demonstrated.

Conclusion

The findings of this report revealed the presence of many sleep-related disorders within the FD population. However, very few studies on this subject are available, and their limited results make it difficult to truly assess the real extent of the prevalence of sleep disturbances among these individuals. There is a need to conduct further studies on this topic, involving a larger group of patients. It is important to note that there are no guidelines available for the treatment of sleep disorders in patients with FD.

Lipidomic Approaches in Common and Rare Cerebrovascular Diseases: The Discovery of Unconventional Lipids as Novel Biomarkers

Stroke remains a major cause of death and disability worldwide. Identifying new circulating biomarkers able to distinguish and monitor common and rare cerebrovascular diseases that lead to stroke is of great importance. Biomarkers provide complementary information that may improve diagnosis, prognosis and prediction of progression as well. Furthermore, biomarkers can contribute to filling the gap in knowledge concerning the underlying disease mechanisms by pointing out novel potential therapeutic targets for personalized medicine. If many "conventional" lipid biomarkers are already known to exert a relevant role in cerebrovascular diseases, the aim of our study is to review novel "unconventional" lipid biomarkers that have been recently identified in common and rare cerebrovascular disorders using novel, cutting-edge lipidomic approaches.

Difficulties in Diagnosing Fabry Disease in Patients with Unexplained Left Ventricular Hypertrophy (LVH): Is the Novel GLA Gene Mutation a Pathogenic Mutation or Polymorphism?

Fabry disease (FD) is an X-linked, lysosomal glycosphingolipid storage disorder that occurs very rarely. Cardiac involvement may comprise of left ventricular hypertrophy (LVH), arrhythmias, conduction abnormalities, heart failure and valvular abnormalities. The goal of this study was to conduct gene analysis for FD in patients suffering from unexplained LVH. 120 patients over the age of 30 who were diagnosed by echocardiography with idiopathic LVH were included in the study. Patients with severe hypertension, intermediate valve disease such as moderate aortic stenosis, known FD, and a family history of autosomal dominant hypertrophic cardiomyopathy were excluded from the study. GLA gene mutations were studied by Sanger sequence analysis in all patients. Of the 120 total patients included in this study, 69 were female (58%) and 51 were male (42%). The mean age was 60.3 ± 15.7. GLA gene mutations were detected in three male patients. The detected mutations are as follows: NM_000169.2:IVS6-10G>A (c.1000-10G>A), NM_000169.2:c.937G>T (p.D313Y) (p.Asp313Tyr) and NM_000169.2:c.941A>T (p.K314M) (p.Lys314Met). Early diagnosis is of vital importance in FD, which can be treated with enzyme replacement. Genetic screening in patients diagnosed with idiopathic LVH by echocardiography is important in the early diagnosis and treatment of FD. Patients over 30 years of age with idiopathic LVH should be screened for FD. Various new polymorphisms can be detected in genetic screening. Identifying new polymorphisms is important for knowing the true mutations in FD.

The prevalence of Fabry disease in a Turkish population with chronic kidney patients

BACKGROUND AND OBJECTIVES

Fabry disease (FD) is an X-linked lysosomal storage disease with various clinical symptoms due to a deficiency of an enzyme called alpha-galactosidase A. The likelihood of nephropathy increases with age and the severity of the mutation in Fabry patients. Fabry disease is difficult to diagnose. The exact incidence and prevalence of Fabry disease are unknown due to its atypical or oligosymptomatic forms.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

GLA gene mutations were examined in patients over the age of 18 who were followed up on with a diagnosis of chronic kidney disease and who had or did not receive renal replacement therapy from October 2017 to December 2019.

RESULTS

A total of 18 sites in 8 locations around Turkey volunteered to participate in the study, including people aged 18 and older with stages 1-5 of chronic kidney disease (CKD) or getting renal replacement therapy. 1904 patients were screened in total. In 13 cases, a D313Y pseudo mutation in the GLA gene was discovered. GLA gene mutations were found and pathologically assessed in four of the tested cases.

CONCLUSIONS

The range of clinical symptoms of Fabry disease, as well as the frequent delays in diagnosis, result in treatment being too late. We believe that screening chronic renal patients at high risk for Fabry disease is warranted.

Fabry Disease Frequency Among Young Cryptogenic Stroke Patients in the City of Edirne, Turkey

BACKGROUND

We sought to determine the incidence of Fabry disease (FD) in young cryptogenic stroke patients who lived in the City of Edirne, Turkey, and to define the clinical features helping to recognize patients with FD.

METHODS

Acute ischemic stroke patients aged 18 to 55 years who were admitted to our hospital between January 2017 and September 2019 were evaluated for inclusion. The screening was performed for α-galactosidase A activity on dried blood spot, and DNA was sequenced for GLA mutation in patients with low-plasma α-galactosidase A activity.

RESULTS

Two proband cases were detected. The first proband patient was identified as having a 427G>A (rs 104894845) (p.A143T) hemizygous mutation along with his family; 3 patients were identified as having the same hemizygous mutation; and 6 patients were identified as having the same heterozygous mutations. The second proband patient was identified as having a c.352C>T (rs 148158093) (p.R118C) heterozygote mutation along with her family; 5 patients were identified as having the same heterozygote mutation; and 1 patient was identified as having the same hemizygous mutation. Our study identified the FD incidence as 3.27%.

CONCLUSIONS

This research is just one of a few studies conducted on FD screening studies in Turkish stroke patients. Our results underlined the importance of considering FD during the etiologic evaluation of young cryptogenic stroke patients, as it is a rare but potentially treatable entity.

Ratio of Fabry disease in patients with idiopathic left ventricular hypertrophy: A single-center study in Turkey

OBJECTIVE

Fabry disease (FD) is a progressive, X-linked inherited disorder of glycosphingolipid metabolism which arises due to deficient or absent activity of lysosomal α-galactosidase A (α-Gal A). This may be associated with increased left ventricular (LV) wall thickness and may mimic the morphological features of hypertrophic cardiomyopathy. The purpose of this study was to define the ratio of occurrence of FD to the manifestation of unexplained left ventricular hypertrophy (LVH).

METHODS

We studied a prospectively assembled a consecutive cohort of 190 patients with unexplained LVH on echocardiography. The criterion for LVH diagnosis was a maximum LV wall thickness of 13 mm or greater. All patients were tested for mutations in the GLA gene.

RESULTS

The majority of patients were male (n=119, 63%) and the mean patient age was 47.2±115 years. In 190 patients diagnosed with LVH, we identified 2 patients (1.05%) with documented GLA mutations [c.427G>A (p.A143T)(p.Ala143Thr)] and [c.937G>T (p.D313Y)(p.Asp313Tyr)]. After the family screening, 3 additional patients with FD were identified in 2 families, including 5 individuals who are now receiving enzyme replacement therapy.

CONCLUSION

We identified 2 index patients with FD and unexplained LVH. Cardiologists should, therefore, be aware of FD in cases of unexplained LVH. Family screening is crucial for the earlier identification of unaffected new patients who may benefit from enzyme replacement therapy.

Patient and observer reported outcome measures to evaluate health-related quality of life in inherited metabolic diseases: a scoping review

Background

Health-related Quality of Life (HrQoL) is a multidimensional measure, which has gained clinical and social relevance. Implementation of a patient-centred approach to both clinical research and care settings, has increased the recognition of patient and/or observer reported outcome measures (PROMs or ObsROMs) as informative and reliable tools for HrQoL assessment. Inherited Metabolic Diseases (IMDs) are a group of heterogeneous conditions with phenotypes ranging from mild to severe and mostly lacking effective therapies. Consequently, HrQoL evaluation is particularly relevant.

Objectives

We aimed to: (1) identify patient and/or caregiver-reported HrQoL instruments used among IMDs; (2) identify the main results of the application of each HrQoL tool and (3) evaluate the main limitations of HrQoL instruments and study design/methodology in IMDs.

Methods

A scoping review was conducted using methods outlined by Arksey and O’Malley. Additionally, we critically analysed each article to identify the HrQoL study drawbacks.

Results

Of the 1954 studies identified, 131 addressed HrQoL of IMDs patients using PROMs and/or ObsROMs, both in observational or interventional studies. In total, we identified 32 HrQoL instruments destined to self- or proxy-completion; only 2% were disease-specific. Multiple tools (both generic and disease-specific) proved to be responsive to changes in HrQoL; the SF-36 and PedsQL questionnaires were the most frequently used in the adult and pediatric populations, respectively. Furthermore, proxy data often demonstrated to be a reliable approach complementing self-reported HrQoL scores. Nevertheless, numerous limitations were identified especially due to the rarity of these conditions.

Conclusions

HrQoL is still not frequently assessed in IMDs. However, our results show successful examples of the use of patient-reported HrQoL instruments in this field. The importance of HrQoL measurement for clinical research and therapy development, incites to further research in HrQoL PROMs’ and ObsROMs’ creation and validation in IMDs.

Electronic supplementary material

The online version of this article (10.1186/s13023-018-0953-9) contains supplementary material, which is available to authorized users.

Evaluating enzyme replacement therapies for Anderson-Fabry disease: commentary on a recent report

Anderson-Fabry disease (AFD) is a rare lysosomal storage disorder. Randomized controlled clinical trials (RCTs) are preferred as the highest category of evidence, but limited availability of robust evidence in rare diseases may necessitate the use of less rigorous evidence. An analysis of cohort studies of enzyme replacement therapies for AFD published in 2017 by El Dib and coworkers made treatment recommendations that contradict previously published findings from RCTs and a systematic Cochrane review. Our commentary outlines concerns regarding selection criteria and statistical methods with their analysis.

Fabry disease in the Spanish population: observational study with detection of 77 patients

Background

Fabry disease is a multisystemic lysosomal storage disorder caused by the impairment of α-galactosidase A. The incidence of this rare disease is underestimated due to delayed diagnosis. Moreover, the management of the identified subjects is often complicated by the detection of variants of unclear diagnostic interpretation, usually identified in screening studies. We performed an observational study based on biochemical and genetic analysis of 805 dried blood spot samples from patients with clinical symptoms or family history of this pathology, which were collected from 109 Spanish hospitals, all over the country.

Results

We identified 77 new diagnosed patients with mutations related to classical Fabry disease, as well as 2 subjects with c.374A > T; p.His125Leu, a possible new mutation that need to be confirmed. Additionally, we detected 8 subjects carrying genetic variants possibly linked to late onset Fabry disease (p.Arg118Cys and p.Ala143Thr), 4 cases with polymorphism p.Asp313Tyr and 36 individuals with single nucleotide polymorphisms in intronic regions of GLA. Five of the identified mutations (c.431delG; c.1182delA; c.374A > T; c.932 T > C; c.125 T > A; c.778G > A), which were associated with a classical phenotype have not been previously described. Moreover 3 subjects presenting complex haplotypes made up by the association of intronic variants presented impaired levels of GLA transcripts and Gb3 deposits in skin biopsy.

Conclusions

Enzymatic screening for Fabry Disease in risk population (2 or more clinical manifestations or family history of the disease) helped to identify undiagnosed patients and unravel the impairment of GLA expression in some subjects with complex haplotypes.

Electronic supplementary material

The online version of this article (10.1186/s13023-018-0792-8) contains supplementary material, which is available to authorized users.

Enzyme replacement therapy for Anderson-Fabry disease: A complementary overview of a Cochrane publication through a linear regression and a pooled analysis of proportions from cohort studies

BACKGROUND

Anderson-Fabry disease (AFD) is an X-linked recessive inborn error of glycosphingolipid metabolism caused by a deficiency of alpha-galactosidase A. Renal failure, heart and cerebrovascular involvement reduce survival. A Cochrane review provided little evidence on the use of enzyme replacement therapy (ERT). We now complement this review through a linear regression and a pooled analysis of proportions from cohort studies.

OBJECTIVES

To evaluate the efficacy and safety of ERT for AFD.

MATERIALS AND METHODS

For the systematic review, a literature search was performed, from inception to March 2016, using Medline, EMBASE and LILACS. Inclusion criteria were cohort studies, patients with AFD on ERT or natural history, and at least one patient-important outcome (all-cause mortality, renal, cardiovascular or cerebrovascular events, and adverse events) reported. The pooled proportion and the confidence interval (CI) are shown for each outcome. Simple linear regressions for composite endpoints were performed.

RESULTS

77 cohort studies involving 15,305 participants proved eligible. The pooled proportions were as follows: a) for renal complications, agalsidase alfa 15.3% [95% CI 0.048, 0.303; I2 = 77.2%, p = 0.0005]; agalsidase beta 6% [95% CI 0.04, 0.07; I2 = not applicable]; and untreated patients 21.4% [95% CI 0.1522, 0.2835; I2 = 89.6%, p<0.0001]. Effect differences favored agalsidase beta compared to untreated patients; b) for cardiovascular complications, agalsidase alfa 28% [95% CI 0.07, 0.55; I2 = 96.7%, p<0.0001]; agalsidase beta 7% [95% CI 0.05, 0.08; I2 = not applicable]; and untreated patients 26.2% [95% CI 0.149, 0.394; I2 = 98.8%, p<0.0001]. Effect differences favored agalsidase beta compared to untreated patients; and c) for cerebrovascular complications, agalsidase alfa 11.1% [95% CI 0.058, 0.179; I2 = 70.5%, p = 0.0024]; agalsidase beta 3.5% [95% CI 0.024, 0.046; I2 = 0%, p = 0.4209]; and untreated patients 18.3% [95% CI 0.129, 0.245; I2 = 95% p < 0.0001]. Effect differences favored agalsidase beta over agalsidase alfa or untreated patients. A linear regression showed that Fabry patients receiving agalsidase alfa are more likely to have higher rates of composite endpoints compared to those receiving agalsidase beta.

CONCLUSIONS

Agalsidase beta is associated to a significantly lower incidence of renal, cardiovascular and cerebrovascular events than no ERT, and to a significantly lower incidence of cerebrovascular events than agalsidase alfa. In view of these results, the use of agalsidase beta for preventing major organ complications related to AFD can be recommended.

Gender Differences in the Application of Spanish Criteria for Initiation of Enzyme Replacement Therapy for Fabry Disease in the Fabry Outcome Survey

Both male/female patients with Fabry disease (FD) may receive enzyme replacement therapy (ERT). Previously published analyses of the Fabry Outcome Survey (FOS; Shire-sponsored) database suggested gender differences in timing of ERT initiation. We assessed alignment of criteria for ERT initiation in the Spanish adult population included in FOS with recommendations of a Spanish national consensus. This retrospective analysis examined baseline clinical data of 88 adults (49 females) enrolled in the FOS database up to August 2014. Thirty-five (39.8%) patients were not receiving ERT: five (12.8%) males and 30 (61.2%) females. Baseline disease severity on the FOS-derived Mainz Severity Score Index was lower in untreated males (median (interquartile range), 0.0 (0.0–1.0)) than treated males (TM; 15.0 (7.5–26.5)), and was similar in untreated and treated females. The percentage of untreated females with at least one criterion for treatment initiation was 76.7% versus 100.0% of treated females (p = 0.0340) and 97.1% (p = 0.0210) of TM. In discordance with Spanish consensus recommendations, a substantial number of females with evidence of FD who might benefit from ERT have not yet initiated treatment. These results suggest unequal gender perceptions with respect to ERT initiation in Spain.

Quality of life in patients with Fabry disease: a systematic review of the literature

Fabry disease (FD), caused by deficiency of the lysosomal enzyme α-galactosidase-A, is a progressive multisystem disease. The disease is X-linked with generally more severe manifestations in males, but can impact on quality of life (QoL) of both male and female patients. The purpose of this literature review is to analyse the currently available data concerning QoL measurement, specifically which questionnaires have been used to measure QoL, how patients with FD score compared to the general population, and the effects of enzyme replacement therapy (ERT) on QoL. Fifty-four articles were relevant for this literature review. Patients with FD had a lower QoL compared to the general population. No definite conclusions could be drawn from the studies on the effect of ERT on QoL; natural history data is scarce, changes observed were limited and the cohorts were of small size. We propose that a FD specific questionnaire be made to accurately assess QoL in patients with FD.

[Comparison of patients from a Spanish Registry of Fabry disease in two periods]

BACKGROUND AND OBJECTIVE

Fabry disease (FD) is a rare X-linked lysosomal storage disorder caused by a deficiency of the enzyme alpha-galactosidase A, that leads to multiorgan dysfunction and premature death. Data from the first 24 Spanish patients enrolled on the Fabry Outcome Survey (FOS) were published in 2004, with a significant increase in the number of patients since then. This manuscript analyzes whether the clinical profile or diagnosis of these patients between the 2 periods has changed.

PATIENTS AND METHODS

In 2009 the FOS included data from 92 patients. Patients included up to 2003 and those included after that year (68) were compared by sex, regarding age at onset of symptoms and diagnosis, severity and previous misdiagnoses. Similar analysis was performed between the index cases (31) and the other patients.

RESULTS

Mean delay in diagnosis was 10 years for both sexes. Male had a classic phenotype, and up to 40% of the females reported symptoms. In females, the enzyme activity seemed to determine disease severity. No differences were observed in any parameter when comparing the patients included in the first period to those included afterwards, nor when comparing index cases with the rest of the patients.

CONCLUSIONS

Registries like FOS have a great value to deepen our understanding of rare diseases. We confirm that women are not just carriers of the disease. There is still a lack of education and awareness in order to include FD in the differential diagnosis of other processes. Complete family studies would allow early diagnosis of this disorder.