Characterization of vertigo and hearing loss in patients with Fabry disease

Dizziness in Fabry Disease

Background/Objectives: Fabry disease is an X-linked lysosomal storage disease. Earlier studies have mentioned dizziness/balance issues and vestibular involvement as a symptom of Fabry disease. Research on the matter remains scarce. This pilot study aims to show the prevalence of dizziness/balance issues and whether it is due to peripheral, central, or other factors. Methods: A Dizziness Handicap Inventory, with added questions, was sent out to 91 Fabry patients to estimate the prevalence of dizziness/balance issues. Additionally, this study reports analyses from eight Fabry patients with self-reported dizziness/balance issues who were offered referrals for in-depth investigations of their condition. All eight underwent a comprehensive oto-neurological examination, Videonystagmography, a Video Head impulse test, vestibular myogenic evoked potential, and audiometry. Results: A total of 55 of the 91 patients with Fabry disease answered the survey. Of these, 78.2% felt symptoms of dizziness/balance issues. The most common form of dizziness/balance issues was short-lasting attacks. All eight ENT-examined patients had normal outer and middle ear conditions. Five of eight Fabry patients had abnormal results in the optokinetic test and audiometry. Conclusions: The survey showed a high prevalence of dizziness/balance issues in Fabry patients. The abnormal optokinetic test suggested a central cause and was the only objective measurement we found that could lead to an explanation for dizziness/balance issues. Polypharmacy was present in all eight examined patients and could also explain the dizziness/balance issues in Fabry patients. There is no other clear pattern regarding the characteristics of dizziness/balance issues in Fabry patients in this exploratory study.

Increased prevalence of peripheral vestibular disorder among patients with Fabry disease

BACKGROUND

Although peripheral vestibular disorder is a non-fatal complication of Fabry disease, fatalities have been reported in some case reports and case series. To date, no studies have examined the relative risk of peripheral vestibular disorder in patients with Fabry disease compared to the general population without the condition. Due to the high prevalence of Fabry disease in East Asia and the potential shared pathogenic pathways between Fabry disease and vasculopathy, we conducted a study using a nationwide population-based dataset to compare the prevalence of peripheral vestibular disorder between patients with Fabry disease and matched comparison patients.

METHODS

Data was sourced from Taiwan's Longitudinal Health Insurance Database 2010. this study consists of 11,668 sampled patients, 2917 study patients with Fabry disease and 8751 propensity-score-matching comparison patients. We conducted multiple logistic regression analysis to study the association between peripheral vestibular disorder and Fabry disease.

RESULTS

The study identified notable differences in the prevalence of various vestibular disorders between the study and comparison groups. Specifically, there was a 7.2% increased prevalence of peripheral vestibular disorder in the study group (28.3%) compared to the comparison group (20.9%), Meniere's disease (5.4% vs. 3.7%), benign paroxysmal positional vertigo (5.1% vs. 3.3%), and other/ unspecified peripheral vestibular dizziness (15.6% vs. 11.8%) (all p < 0.001). The odds ratios for PVD, MD, BPPV, and other PVD were 1.44 (95% CI = 1.29-1.60), 1.50 (95% CI = 1.23-1.83), 1.59 (95% CI = 1.30-1.95), and 1.40 (95% CI = 1.24-1.58), respectively, among the Fabry disease group relative to the comparison group after adjusting for age, monthly income, geographic location, urbanization level, hyperlipidemia, diabetes, coronary heart disease, and hypertension.

CONCLUSION

This study found that patients with Fabry disease had increased prevalence of peripheral vestibular disorder.

[Neuro-otological manifestations in Fabry disease-a retrospective single center study]

BACKGROUND

Fabry disease (FD) is one of the X‑linked lysosomal storage diseases that can affect any organ. They have a specific lysosomal dysfunction in common, which results in substrate accumulation in lysosomes instead of metabolite degradation. Due to the deficiency/absence of α‑galactosidase, globotriaosylceramides (Gb3) are deposited in lysosomes of the organs. In addition to acroparesthesia, angiokeratomas, autonomic dysfunction, vortex keratopathies, ischemic cerebral or cardiac complications and chronic renal failure, also vestibulocochlear dysfunctions with sudden or progressive asymmetric hearing loss, tinnitus and vertigo may be observed.

PATIENTS AND METHODS

In this retrospective study, 33 patients (men = 16 and women = 17) with FD were evaluated. All patients presented to us in interdisciplinary cooperation as part of routine examinations by the specialized center for lysosomal storage diseases of the in-house department of nephrology. This presentation is carried out as a screening examination independent of neuro-otological symptoms.

RESULTS

The mean age at diagnosis was 34.76 (±11.55) years. The first presentation in our ENT department was at 40.45 (±11.71) years. We were able to demonstrate a significant correlation between neurological symptoms or apoplexy and hearing loss (p = 0.001) and between cardiac manifestations and hearing loss (p = 0.024).

CONCLUSION

Hearing loss is a potential symptom of Fabry disease and is not limited to the classic male phenotype. Due to possible positive correlations with neurological and cardiological manifestations of the disease, routine ENT screening examinations should be carried out to be able to identify and treat neuro-otological deficits at an early stage. In addition, FD should also be considered and tested as a differential diagnosis, especially in younger patients with sudden unilateral or bilateral hearing loss and a family history.

Investigation of ocular involvement in patients with Fabry disease

PURPOSE

To investigate ocular abnormalities in Fabry disease (FD).

METHODS

Forty-five patients with FD diagnosed by genetic analysis were enrolled in a single medical centre. The following ocular examinations were performed: slit-lamp examination, ophthalmic fundus imaging, in vivo confocal microscopy (IVCM) and optical coherence tomography (OCT). The prevalences of typical abnormalities in the cornea, conjunctiva and retina were recorded; their differences between hemizygote and heterozygote were compared.

RESULTS

In this study, the prevalence of corneal verticillata was 97.8% (44/45). Corneal examination with IVCM demonstrated hyper-reflective intracellular inclusions located within basal epithelial cells. Conjunctival vessel malformations were observed in 64.4% (29/45) of patients, and retinal vessel tortuosity was observed in 62.2% (28/45) of patients. OCT revealed many strong hyper-reflective foci (HRF) in the inner retinal layer (in 66.7% [30/45] of patients); these foci may represent retinal vascular plexi. The prevalences of conjunctival vessel malformation, retinal vessel tortuosity and HRF were higher in hemizygote than in heterozygote.

CONCLUSIONS

Corneal verticillata, HRF on OCT, conjunctival vessel malformation and retinal vessel tortuosity exhibit high prevalence in patients with FD. These ocular manifestations are characteristic and easily accessible; thus, they should be considered diagnostic criteria for FD.

Association of Fabry Disease with Hearing Loss, Tinnitus, and Sudden Hearing Loss: A Nationwide Population-Based Study

Hearing loss and the related otologic manifestations are receiving increased scrutiny as significant causes of morbidity in Fabry disease. However, the relative risks of auditory deficits among patients with Fabry disease relative to the general population without a diagnosis of Fabry disease have not been studied. This study aims to explore the associations between Fabry disease and hearing-related manifestations using a nationwide population-based dataset. We identified study patients for this cross-sectional study from the 2015−2017 claims databases of the Taiwan Longitudinal Health Insurance Database 2005. We first identified 2312 patients aged over 20 years with a diagnosis of Fabry disease. We used propensity score matching to select five comparison patients per patient with Fabry disease and 11,560 comparison patients without Fabry disease. We used multivariable logistic regressions to estimate the odds ratios (ORs) and corresponding 95% confidence intervals (CIs) for tinnitus, hearing loss, and sudden deafness among Fabry disease patients vs. comparison patients. Chi-square tests showed statistically significant differences between patients with and without Fabry disease in the prevalence rates of tinnitus (16.7% vs. 11.7%, p < 0.001), hearing loss (7.5% vs. 6.2%, p = 0.014) and sudden deafness (1.7% vs. 1.0%, p = 0.005). Multiple logistic regression revealed that patients with Fabry disease were more likely to suffer from tinnitus, hearing loss and sudden deafness, with adjusted odds ratios of 1.513 (95% CI = 1.336−1.713), 1.246 (95% CI = 1.047−1.483), and 1.681 (95% CI = 1.166−2.423), respectively. We found that Fabry disease is significantly associated with certain auditory manifestations, including hearing loss, sudden deafness, and tinnitus.

Development and validation of a disease-specific quality of life scale for adult patients with Fabry disease in Japan

Background

Fabry disease is a rare X-linked lysosomal storage disorder. It is associated with physical distress and social challenges that may affect adults differently compared to pediatric patients. However, there is no disease-specific quality of life (QOL) scale that can provide a detailed assessment of QOL for adults with Fabry disease. Therefore, we aimed to determine the factor structure and assess the validity of a scale that was created to assess the QOL of adult patients with Fabry disease. This study was conducted in two phases. First, scale feasibility was confirmed through a questionnaire survey of nine patients. Second, a cross-sectional questionnaire survey of patients (aged ≥ 18 years) diagnosed with Fabry disease was conducted. Item development and refinement were conducted based on guidelines for scale development. Exploratory factor analysis was used to clarify the factor structure and confirm internal consistency. As a measure of QOL, construct validity was of the scale was verified based on its correlations with the Short Form-8 (SF-8) scale.

Results

The newly created Adult Fabry Disease QOL (AFQOL) scale comprises 39 items that cover five factors: “neuropathic pain and abdominal symptoms,” “impact on work and school,” “relationship challenges,” “ophthalmologic and otolaryngologic symptoms,” and “cardiovascular and renal symptoms.” Cronbach’s alpha coefficient for all factors was above 0.8, and the AFQOL total scores were significantly correlated with the physical and mental components of the SF-8 (rs = − 0.508 and − 0.400, respectively).

Conclusions

The AFQOL scale assesses physical symptoms and social difficulties experienced by adult patients with Fabry disease. A strength of the scale is its ability to assess the impact of work and relationships on patients. The scale can be useful in objectively assessing QOL for a group or for individual patients. Future research should explore further aspects of the scale’s validity and reliability.

Neurological Manifestations of Fabry Disease: Literature Review

BACKGROUND: Fabry disease (FD) or Anderson FD is a hereditary disease belonging to the group of lysosomal storage diseases caused by decreased or absent activity of the enzyme α-galactosidase A. Enzyme deficiency leads to accumulation of glycospholipids in the lysosomes of cells of various organs, including the heart, kidneys, nervous system, and vascular endothelium. The complexity of the diagnosis of FD is due to the variety of its symptoms, the simultaneous involvement of many organs and systems. At present, possible pathogenetic treatment of the disease is enzyme replacement therapy, but its effectiveness is reduced in the later stages of the disease, when there are irreversible abnormal changes in vital organs and systems. In this regard, an urgent task is the early diagnosis of FD. AIM: Determination of neurological manifestations of FD as well as clinical criteria for screening for FD. MATERIALS AND METHODS: We analyzed cohort studies, randomized controlled trials, systematic reviews and meta-analyses, case-control studies, and case series from scientific medical databases: PubMed, Web of Science, Google Scholar in Russian, and English languages. CONCLUSION: The authors found that lesions of the nervous system in FD are detected in more than 80% of patients and can manifest as isolated or combined lesions of both the central and peripheral and autonomic nervous systems.

Translation of quality of life scale for pediatric patients with Fabry disease in Japan

Introduction

Methods

Results

Conclusion

Fabry's Disease: The Utility of a Multidisciplinary Screening Approach

(1) Background: As a lysosomal storage disorder, Fabry’s disease (FD) shows variable clinical manifestations. We applied our multidisciplinary approach to identify any organ damage in a sample of adult patients with different pathogenic variants. (2) Methods: 49 participants (mean age 44.3 ± 14.2 years; 37 females), underwent a multidimensional clinical and instrumental assessment. (3) Results: At diagnosis, mean enzymatic activity was 5.2 ± 4.6 nM/mL/h in females and 1.4 ± 0.5 nM/mL/h in males (normal values > 3.0), whereas globotriaosylsphingosine was 2.3 ± 2.1 nM/L in females and 28.7 ± 3.5 nM/L in males (normal values < 2.0). Overall, cardiovascular, neurological, and audiological systems were the most involved, regardless of the variant detected. Patients with classic variants (10) showed typical multiorgan involvement and, in some cases, prevalent organ damage (cardiovascular, neurological, renal, and ocular). Those with late-onset variants (39) exhibited lower occurrence of multiorgan impairment, although some of them affected the cardiovascular and neurological systems more. In patients with lower enzymatic activity, the most frequent involvement was neurological, followed by peripheral vascular disease. (4) Conclusions: FD patients exhibited wide phenotypic variability, even at single-organ level, likely due to the individual genetic mutation, although other factors may contribute. Compared to the conventional management, a multidisciplinary approach, as that prompted at our Center, allows one to achieve early clinical detection and management.

Efficient delivery of adeno-associated virus (AAV) into inner ear in vivo via trans-stapes route in adult guinea pig

Adeno-associated virus (AAV) are potent vectors to achieve treatment against hearing loss resulting from genetic defects. However, the effects of delivery routes and the corresponding transduction efficiencies for clinical applications remain elusive. Here, we screened AAV vectors of three serotypes (AAV 8, 9 and Anc80L65) into the inner ears of adult normal guinea pigs through trans-stapes (oval window) and trans-round window delivery routes in vivo. Trans-stapes route is akin to stape surgeries in humans. Then, auditory brainstem response (ABR) measurements were conducted to evaluate postoperative hearing, and inner ear tissues were harvested for transduction efficiency analysis. Results showed that AAV8 targeted partial inner hair cells (IHCs) in cochlear basal turn; AAV9 targeted IHCs in cochlear basal and second turn, also a part of vestibular hair cells (VHCs). In contrast, Anc80L65 contributed to GFP signals of 80%-95% IHCs and 67%-91% outer hair cells (OHCs), as well as 69% VHCs via the trans-round window route, with 15-20 dB ABR thresholds shifts. And, via trans-stapes (oval window) route, there were 71%-90% IHCs and 42%-81% OHCs, along with 64% VHCs demonstrating GFP positive, and the ABR thresholds shifts were within 10 dB. This study revealed AAV could be efficiently delivered into mammalian inner ear cells in vivo via trans-stapes (oval window) route with postoperative hearing preservation, and both delivery routes showed promise of virus-based clinical translation of hearing impairment treatment.

Prevalence of Fabry disease in men with tinnitus and sensorineural hearing loss

Fabry disease (FD) is a lysosomal storage disorder caused by pathogenic mutations in the alpha-galactosidase A (AGALA) encoding gene region. This rare disease affects several organs including the cochlea-vestibular system. Tinnitus and sensorineural hearing loss (SNHL) are reported among otoneurological symptoms. Early and correct diagnosis of FD is important with a view to available therapy. The aim of the study was to screen for alpha-galactosidase deficiency in men with tinnitus/SNHL. A prospective multicentric study including consecutive patients with SNHL confirmed by tone audiometry or tinnitus evaluated (10/2016-8/2019). The diagnosis of AGALA deficiency was done by dry blood spot method using a threshold of 1.2 µmol/l/h. Only men aged 18-60 were included. 181 patients were subject to evaluation. SNHL was reported in 126 (70%) patients, 50 (28%) patients had unilateral, 76 (42%) patients had bilateral SNHL. Tinnitus was found in 161 (89%) patients, unilateral in 96 (53%) and bilateral in 65 (36%) patients. Suspected FD was not detected in any patient; alpha-galactosidase The AGALA values ranged 1.5-8.8 µmol/l/h, an average of 3.4 µmol/l/h. None of the 181 patients participating in the study had AGALA levels below the threshold 1.2 µmol/l/h. The occurrence of tinnitus and sensorineural hearing loss in men appears to be an irrelevant clinical sign for FD systematic screening.

Cochleovestibular involvement in patients with Fabry disease: data from the multicenter cohort FFABRY

PURPOSE

Fabry disease (FD) is a lysosomal storage disease responsible for cochleovestibular involvement. Exact prevalence and pathophysiological mechanisms behind ENT affections are still poorly known. Treating FD with enzyme replacement therapy (ERT) does not seem to significantly improve the ENT symptoms, while the impact of migalastat has yet to be determined.

METHODS

We carried out a retrospective multi-centre study on 47 patients from the FFABRY cohort who had an ENT consultation in the context of their FD. The information collected were as follows: clinical examination, videonystagmoscopy, pure-tone speech audiometry, videonystagmography or VHIT (Video Head Impulse Test). Severe hearing loss was defined as greater than 70 dB.

RESULTS

The median age of our cohort was 52 years with a non-negligible proportion of non-classic variants and female carriers. 72.3% of the patients complained of at least one of the following symptoms: hearing loss, tinnitus or vertigo. Pure-tone audiometry was abnormal in 61.7% of the patients (29/47), while speech audiometry was abnormal for 41.7% of the patients. The age of the patients and hypertrophic cardiomyopathy were significantly associated with the existence of an anomaly in pure-tone audiometry results. Severe hearing loss (> 70 dB) was significantly more common in male patients.

DISCUSSION

Hearing loss is particularly frequent in FD and is not limited to classic phenotypes. Close ENT follow-up is essential for Fabry patients to detect those who might benefit from hearing aid. Further studies are needed to define the impact of migalastat on cochleovestibular symptoms.

Platelet and myeloid cell phenotypes in a rat model of Fabry disease

Fabry disease results from a deficiency of the lysosomal enzyme ⍺-Galactosidase-A (⍺-Gal A) and is estimated to occur in approximately 1:4100 live births. Characteristic of the disease is the accumulation of α-Gal-A substrates, primarily the glycosphingolipids (GSLs) globotriaosylceramide and globotriaosylsphingosine. Thrombotic events are a significant concern for Fabry patients, with strokes contributing to a significant decrease in overall lifespan. Currently, the mechanisms underlying the increased risk of thrombotic events experienced by Fabry patients are incompletely defined. Using a rat model of Fabry disease, we provide an improved understanding of the mechanisms linking GSL accumulation to thrombotic risk. We found that ⍺-Gal A-deficient rats accumulate myeloid-derived leukocytes at sites of GSL accumulation, including in the bone marrow and circulation, and that myeloid-derived leukocyte and megakaryocyte populations were prominent among cell types that accumulated GSLs. In the circulation, ⍺-Gal A-deficient rats had increases in cytokine-producing cell types and a corresponding elevation of pro-inflammatory cytokines. Lastly, circulating platelets from ⍺-Gal A-deficient rats accumulated a similar set of ⍺-Galactosidase-A substrates as was observed in megakaryocytes in the bone marrow, and exhibited increased platelet binding to fibrinogen in microfluidic and flow cytometric assays.

Hot topics in Fabry disease

Fabry disease is a rare inborn error of the enzyme α-galactosidase (α-Gal) and results in lysosomal substrate accumulation in tissues with a wide range of clinical presentations. The disease has attracted a lot of interest over the last years, in particular since enzyme replacement therapy (ERT) has become widely available in 2001. With rising awareness and rising numbers of (diagnosed) patients, physicians encounter new challenges. Over 900 α-Gal gene mutations are currently known, some with doubtful clinical significance, posing diagnostic and prognostic difficulties for the clinician and a lot of uncertainty for patients. Another challenge are patients who develop neutralising antibodies to ERT, which possibly leads to reduced therapy effectiveness. In this article, we summarise the latest developments in the science community regarding diagnostics and management of this rare lysosomal storage disorder and offer an outlook to future treatments.