Novel mutation of COG5 in a Taiwanese girl with congenital disorders of glycosylation manifesting as developmental delay

We are documenting the case of An 11-year-old girl who has been followed up at our out-patient clinic since birth with clinical presentations including intrauterine growth restriction, recurrent periodic fever in infancy, hypotonia, global developmental delay, liver function impairment with cirrhotic changes, and clinodactyly. Congenital abnormalities were suspected but a series of examinations including brain MRI, liver biopsy and muscle biopsy yielded insignificant findings. Whole genome sequencing (WGS) was conducted and revealed three novel mutations (c2T > G, c1826T > C, c.556-560delAGTAAinsCT) of the COG5 gene. A diagnosis of COG5-congenital disorders of glycosylation (COG5-CDG, or CDG IIi), with neurologic presentation was established. Sanger sequencing in the patient and her parents confirmed the compound heterozygous mutation. Upon literature review, we identified the patient as the first case of COG5-CDG in Taiwan. Our study enhances the clarity of the correlation between the mutative genes and the presentation of COG5-CDG.

Novel Manifestation of Corneal Dystrophy After Keratorefractive Surgery

PURPOSE

This study aimed to report cases of bilateral corneal Bowman layer deposits in 4 patients with a history of keratorefractive surgery. To our knowledge, this condition has not previously been reported and should be distinguished from granular corneal dystrophy type 2 and other corneal dystrophies.

METHODS

We reviewed all available medical records that were collected between January 2010 and December 2021 at a tertiary referral center and performed whole-exome sequencing to provide diagnostic information.

RESULTS

Four patients exhibited similar bilateral corneal deposits that were observed more than 10 years after keratorefractive surgery. The patients' ages ranged from 36 to 53 years; 3 of the 4 patients were female. Three patients received laser in situ keratomileusis surgery, and 1 received radial keratotomy. All 4 patients denied having a family history of ocular diseases and reported an uneventful postoperative course. On examination, the best-corrected visual acuity ranged from 6/10 to 6/6 in all 4 patients. Slit-lamp examination revealed bilateral superficial corneal deposits involving the central cornea, and anterior segment optical coherence tomography revealed hyperreflective deposits located in the Bowman layer. Such unique manifestations suggested corneal dystrophy; thus, whole-exome sequencing was performed on all 4 patients. Only 1 patient exhibited a missense mutation in TGFBI . We further analyzed common de novo mutations to explore possible candidate genes associated with this presentation.

CONCLUSIONS

We report a rare entity of presumed corneal dystrophy with deposits located in the Bowman layer in 4 patients who had received keratorefractive surgery. Clarifying the underlying pathophysiology and genetic predisposition of this disease may aid in diagnosing and preventing potential complications after keratorefractive surgery.

Mechanistic Insights into Dibasic Iminosugars as pH-Selective Pharmacological Chaperones to Stabilize Human α-Galactosidase

The use of pharmacological chaperones (PCs) to stabilize specific enzymes and impart a therapeutic benefit is an emerging strategy in drug discovery. However, designing molecules that can bind optimally to their targets at physiological pH remains a major challenge. Our previous study found that dibasic polyhydroxylated pyrrolidine 5 exhibited superior pH-selective inhibitory activity and chaperoning activity for human α-galactosidase A (α-Gal A) compared with its monobasic parent molecule, 4. To further investigate the role of different C-2 moieties on the pH-selectivity and protecting effects of these compounds, we designed and synthesized a library of monobasic and dibasic iminosugars, screened them for α-Gal A-stabilizing activity using thermal shift and heat-induced denaturation assays, and characterized the mechanistic basis for this stabilization using X-ray crystallography and binding assays. We noted that the dibasic iminosugars 5 and 20 protect α-Gal A from denaturation and inactivation at lower concentrations than monobasic or other N-substituted derivatives; a finding attributed to the nitrogen on the C-2 methylene of 5 and 20, which forms the bifurcated salt bridges (BSBs) with two carboxyl residues, E203 and D231. Additionally, the formation of BSBs at pH 7.0 and the electrostatic repulsion between the vicinal ammonium cations of dibasic iminosugars at pH 4.5 are responsible for their pH-selective binding to α-Gal A. Moreover, compounds 5 and 20 demonstrated promising results in improving enzyme replacement therapy and exhibited significant chaperoning effects in Fabry cells. These findings suggest amino-iminosugars 5 and 20 as useful models to demonstrate how an additional exocyclic amino group can improve their pH-selectivity and protecting effects, providing new insights for the design of pH-selective PCs.

Quantitative DNA Methylation Analysis and Epigenotype-Phenotype Correlations in Taiwanese Patients with Silver-Russell Syndrome

Background: Silver-Russell syndrome (SRS; OMIM #180860) is a clinically and genetically heterogeneous imprinting disorder characterized by prenatal and postnatal growth failure. The aim of this study was to identify the epigenotype-phenotype correlations in these patients using quantitative DNA methylation analysis. Methods: One hundred and eighty-three subjects clinically suspected of having SRS were referred for diagnostic testing by the methylation profiling of H19-associated imprinting center (IC) 1 and imprinted PEG1/MEST regions using methylation-specific high-resolution melting analysis and methylation quantification with the MassARRAY assay. Correlations between quantitative DNA methylation status and clinical manifestations of the subjects according to the Netchine-Harbison (N-H) clinical scoring system for SRS were analyzed. Results: Among the 183 subjects, 90 had a clinical diagnosis of SRS [N-H score ≥ 4 (maximum = 6)] and 93 had an SRS score < 4. Molecular lesions were detected in 41% (37/90) of the subjects with a clinical diagnosis of SRS, compared with 3% (3/93) of those with an N-H score < 4. The IC1 methylation level was negatively correlated with the N-H score. The molecular diagnosis rate was positively correlated with the N-H score. Thirty-one subjects had IC1 hypomethylation (IC1 methylation level <35% by the MassARRAY assay), seven had maternal uniparental disomy 7, and two had pathogenic copy number variants. Among the 90 subjects with an N-H score ≥ 4, the IC1 methylation level was significantly different between those with or without some clinical SRS features, including birth length ≤ 10th centile, relative macrocephaly at birth, normal cognitive development, body asymmetry, clinodactyly of the fifth finger, and genital abnormalities. Conclusions: This study confirmed the suitability of the N-H clinical scoring system as clinical diagnostic criteria for SRS. Quantitative DNA methylation analysis using the MassARRAY assay can improve the detection of epigenotype-phenotype correlations, further promoting better genetic counseling and multidisciplinary management for these patients.

Cardiomyocyte Globotriaosylceramide Accumulation in Adult Male Patients with Fabry Disease and IVS4 + 919G>A GLA Mutation is Progressive with Age and Correlates with Left Ventricular Hypertrophy and Reduced Left Ventricular Ejection Fraction

Background

While cardiovascular complications are the most common cause of mortality in Fabry disease, the relationship between globotriaosylceramide (GL-3) accumulation, the hallmark of Fabry cardiomyopathy, and cardiac hypertrophy has not been fully elucidated.

Methods

We developed unbiased stereology protocols to quantify the ultrastrcture of Fabry cardiomyopathy. Endomyocardial biopsies from 10 adult male enzyme replacement therapy naïve Fabry patients with IVS4 + 919G>A GLA mutation were studied. The findings were correlated with cardiac MRI and clinical data.

Results

Ultrastructural parameters showed significant relationships with key imaging and clinical and functional variables. Average cardiomyocyte volume and GL-3 volume per cardiomyocyte were progressively increased with age. Eighty-four percent of left ventricular mass index (LVMI) variability was explained by cardiomyocyte nuclear volume, age and plasma globotriaosylsphingosine with cardiomyocyte nuclear volume being the only independent predictor of LVMI. Septal thickness was directly and left ventricular ejection fraction (LVEF) was inversely correlated with cardiomyocyte GL-3 accumulation. Sixty-five percent of left ventricular ejection fraction (LVEF) variability was explained by cardiomyocyte GL3 volume, serum α-galactosidase-A activity and age with cardiomyocyte GL3 volume being the only independent predictor of LVEF. Residual α-galactosidase-A activity was directly correlated with myocardial microvasculature density.

Conclusions

The unbiased stereological methods introduced in this study unraveled novel relationships between cardiomyocyte structure and important imaging and clinical parameters. These novel tools can help better understand Fabry cardiomyopathy pathophysiology.

Consensus recommendations for the treatment and management of patients with Fabry disease on migalastat: a modified Delphi study

Objective

Fabry disease is a progressive disorder caused by deficiency of the α-galactosidase A enzyme (α-Gal A), leading to multisystemic organ damage with heterogenous clinical presentation. The addition of the oral chaperone therapy migalastat to the available treatment options for Fabry disease is not yet universally reflected in all treatment guidelines. These consensus recommendations are intended to provide guidance for the treatment and monitoring of patients with Fabry disease receiving migalastat.

Methods

A modified Delphi process was conducted to determine consensus on treatment decisions and monitoring of patients with Fabry disease receiving migalastat. The multidisciplinary panel comprised 14 expert physicians across nine specialties and two patients with Fabry disease. Two rounds of Delphi surveys were completed and recommendations on the use of biomarkers, multidisciplinary monitoring, and treatment decisions were generated based on statements that reached consensus.

Results

The expert panel reached consensus agreement on 49 of 54 statements, including 16 that reached consensus in round 1. Statements that reached consensus agreement are summarized in recommendations for migalastat treatment and monitoring, including baseline and follow-up assessments and frequency. All patients with Fabry disease and an amenable mutation may initiate migalastat treatment if they have evidence of Fabry-related symptoms and/or organ involvement. Treatment decisions should include holistic assessment of the patient, considering clinical symptoms and organ involvement as well as patient-reported outcomes and patient preference. The reliability of α-Gal A and globotriaosylsphingosine as pharmacodynamic response biomarkers remains unclear.

Conclusion

These recommendations build on previously published guidelines to highlight the importance of holistic, multidisciplinary monitoring for patients with Fabry disease receiving migalastat, in addition to shared decision-making regarding treatments and monitoring throughout the patient journey. GRAPHICAL ABSTRACT.

Ophthalmic characteristics and retinal vasculature changes in Williams syndrome, and its association with systemic diseases

BACKGROUND

We aim to characterise the ophthalmic findings and retinal vasculature changes in patients with WS, and to analyse the correlation between ophthalmic manifestations and the associated systemic diseases.

METHODS

This retrospective case-control study included 27 WS patients and 28 age-matched healthy participants. Stellate pattern of iris, central macular thickness (CMT), foveal width, retinal vessel diameter, superficial vascular density (SVD) of macula and foveal avascular zone (FAZ) were compared between WS patients and healthy participants.

RESULTS

Twenty-five patients (93%) had the classic stellate iris presentation. Compared with healthy controls, WS patients had decreased CMT, increased foveal width and a lower SVD of macula (all P < 0.001). Significantly decreased mean retinal arterial (117.9 ± 9.9 µm vs. 133.0 ± 6.7 µm in WS and controls, respectively; p < 0.001) and venous (158.9 ± 11.2 µm vs. 174.0 ± 8.0 µm in WS and controls, respectively; p < 0.001) outer diameters, as well as mean arterial wall thickness (11.2 ± 1.3 µm vs. 12.2 ± 0.8 µm in WS and controls, respectively; p < 0.01) were found in WS. Stellate iris grading was significantly associated with CMT, foveal width, retinal vessel diameter (all p < 0.05), and a significant increase in the odds of having hypertension (Odds ratio (OR), 5.63; P < 0.05). The severity of stellate iris in WS seemed to have the trend of increasing risk of having pulmonary stenosis, tricuspid regurgitation and mitral regurgitation.

CONCLUSIONS

This study provides the first in vivo evidence reflecting current knowledge on vessel morphology in WS patients that deficient circumferential growth is the predominant pathophysiologic changes resulting from elastin deficiency. The ophthalmic characteristics may serve as a complementary tool to diagnose and follow-up patients suffering from WS.

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.

Novel mutation of IFT140 in an infant with Mainzer-Saldino syndrome presenting with retinal dystrophy

A seven-month-old girl presented with bilateral roving nystagmus, hyperopia, and retinal dystrophy, and was brought to our ophthalmology clinic. Visual-evoked potentials (VEPs) were non-recordable in both the eyes. No other systemic symptoms or abnormalities were observed. Whole exome sequencing (WES) identified a compound heterozygous mutation in the IFT140 gene: c.1990G > A (p. Glu664Lys) and c.2214_2217del (p.Asp738GlufsTer47). The genetic results support a diagnosis of Mainzer-Saldino syndrome (MSS). Importantly, c.2214_2217del is a novel mutation in the IFT140 gene. Although the patient presents with isolated retinal dystrophy, it is crucial to monitor renal function overtime. Taken together, our results reinforce the role of IFT140 in syndromic ciliopathies. This report also highlights the role of combined WES approaches in identifying underlying mutations in infants presenting with isolated retinal dystrophy, considering MSS may present differently over time.

•

A novel mutation in IFT140 was found to cause Mainzer-Saldino syndrome (MSS).

•

MSS may present as isolated retinal dystrophy in infant, and genetic testing plays a crucial role in diagnosis.

•

Patients with MSS should receive systemic follow-up, particularly renal function.

Long-term outcomes of very early treated infantile-onset Pompe disease with short-term steroid premedication: experiences from a nationwide newborn screening programme

BACKGROUND

Starting enzyme replacement therapy (ERT) before severe irreversible muscular damage occurs is important in infantile-onset Pompe disease (IOPD). This long-term follow-up study demonstrates our diagnostic and treatment strategies for IOPD and compares our clinical outcomes with those of other medical centres.

METHODS

In this long-term follow-up study, we analysed the outcomes of very early ERT with premedication hydrocortisone in patients with IOPD. Out of 1 228 539 infants screened between 1 January 2010 and 28 February 2021, 33 newborns had confirmed IOPD in Taipei Veterans General Hospital. Twenty-six were regularly treated and monitored at Taipei Veterans General Hospital. Echocardiographic parameters, biomarkers, IgG antibodies against alglucosidase alpha, pulmonary function variables and developmental status were all assessed regularly over an average follow-up duration of 6.18±3.14 years. We compared the long-term treatment outcomes of our patients with those of other research groups.

RESULTS

The average age at ERT initiation was 9.75±3.17 days for patients with classic IOPD. The average of the latest antialglucosidase alpha IgG titre was 669.23±1159.23. All enrolled patients had normal heart sizes, motor milestones, cognitive function and pulmonary function that were near-normal to normal. Compared with patients in other studies, our patients had better outcomes in all aspects.

CONCLUSION

Very early ERT using our rapid diagnostic and treatment strategy enabled our patients with IOPD to have better outcomes than patients in other medical centres.

Newborn Screening Program for Mucopolysaccharidosis Type II and Long-Term Follow-Up of the Screen-Positive Subjects in Taiwan

Background: Mucopolysaccharidosis II (MPS II) is an X-linked disorder resulting from a deficiency in lysosomal enzyme iduronate-2-sulfatase (IDS), which causes the accumulation of glycosaminoglycans (GAGs) in the lysosomes of many tissues and organs, leading to progressive cellular dysfunction. An MPS II newborn screening program has been available in Taiwan since 2015. The aim of the current study was to collect and analyze the long-term follow-up data of the screen-positive subjects in this program. Methods: From August 2015 to April 2022, 548,624 newborns were screened for MPS II by dried blood spots using tandem mass spectrometry, of which 202 suspected infants were referred to our hospital for confirmation. The diagnosis of MPS II was confirmed by IDS enzyme activity assay in leukocytes, quantitative determination of urinary GAGs by mass spectrometry, and identification of the IDS gene variant. Results: Among the 202 referred infants, 10 (5%) with seven IDS gene variants were diagnosed with confirmed MPS II (Group 1), 151 (75%) with nine IDS gene variants were classified as having suspected MPS II or pseudodeficiency (Group 2), and 41 (20%) with five IDS gene variants were classified as not having MPS II (Group 3). Long-term follow-up every 6 months was arranged for the infants in Group 1 and Group 2. Intravenous enzyme replacement therapy (ERT) was started in four patients at 1, 0.5, 0.4, and 0.5 years of age, respectively. Three patients also received hematopoietic stem cell transplantation (HSCT) at 1.5, 0.9, and 0.6 years of age, respectively. After ERT and/or HSCT, IDS enzyme activity and the quantity of urinary GAGs significantly improved in all of these patients compared with the baseline data. Conclusions: Because of the progressive nature of MPS II, early diagnosis via a newborn screening program and timely initiation of ERT and/or HSCT before the occurrence of irreversible organ damage may lead to better clinical outcomes. The findings of the current study could serve as baseline data for the analysis of the long-term effects of ERT and HSCT in these patients.

Twenty years of the Fabry Outcome Survey (FOS): insights, achievements, and lessons learned from a global patient registry

Background

Patient registries provide long-term, real-world evidence that aids the understanding of the natural history and progression of disease, and the effects of treatment on large patient populations with rare diseases. The year 2021 marks the 20th anniversary of the Fabry Outcome Survey (FOS), an international, multicenter, observational registry (NCT03289065). The primary aims of FOS are to broaden the understanding of Fabry disease (FD), an X-linked lysosomal storage disorder, and to improve the clinical management of affected patients. Here, we review the history of FOS and the analyses and publications disseminated from the registry, and we discuss the contributions FOS studies have made in understanding FD.

Results

FOS was initiated in April 2001 and, as of January 2021, 4484 patients with a confirmed diagnosis and patient informed consent have been enrolled from 144 centers across 26 countries. Data from FOS have been published in nearly 60 manuscripts on a wide variety of topics relevant to FD. Analyses of FOS data have investigated the long-term effectiveness and safety of enzyme replacement therapy (ERT) with agalsidase alfa and its effects on morbidity and mortality, as well as the benefits of prompt and early treatment with agalsidase alfa on the progression of cardiomyopathy and the decline in renal function associated with FD. Based on analyses of FOS data, ERT with agalsidase alfa has also been shown to improve additional signs and symptoms of FD experienced by patients. FOS data analyses have provided a better understanding of the natural history of FD and the specific populations of women, children, and the elderly, and have provided practical tools for the study of FD. FOS has also provided methodology and criteria for assessing disease severity which contributed to the continuous development of medical practice in FD and has largely improved our understanding of the challenges and needs of long-term data collection in rare diseases, aiding in future rare disease real-world evidence studies.

Conclusion

FOS over the last 20 years has substantially increased the scientific knowledge around improved patient management of FD and continues to expand our understanding of this rare disease.

Safety and long-term outcomes of early liver transplantation for pediatric methylmalonic acidemia patients

BACKGROUND

LT is a treatment option for MMA patients, but renal function impairment is one of the long-term concerns. The aim of this study was to evaluate the outcomes of early LT in these patients.

METHODS

A total of 11 MMA mut-type patients (including 10 mut0 cases and 1 mut-case) who received LT in our institute were reviewed. Their metabolic profiles were compared between the pre/post-transplant periods. Their immunosuppressant and renal function changes after transplantation were assessed.

RESULTS

After a mean follow-up of 97.5 ± 38.4 months, there were two deaths, and the actual survival rate was 81.8%. Their metabolic profiles had improved (mean blood ammonia level 366.8 ± 105.5 vs. 53.1 ± 17.4 μg/dl, p < .001; C3/C2 ratio 2.68 ± 0.87 vs. 0.73 ± 0.22, p = .003; mean urine MMA level 920.5 ± 376.6 vs. 196.2 ± 85.4, p = .067), and hospital stays were decreased (78.8 ± 74.5 vs. 7.4 ± 7.0 days/year, p = .009) after transplantation. The mean age at transplant was 1.81 ± 2.02 years old, and nine of these patients received LT before the age of 1.5 years old (early LT). Under prospective immunosuppressant dose reduction, three of these early LT patients discontinued the drug and were sustained for more than 5 years. Most of the patients had a preserved renal function, and no patient is currently on dialysis.

CONCLUSIONS

In addition to the improvement in the metabolic parameters, early LT in MMA patients may allow for a dose reduction of the immunosuppressant, and the patient's renal function could be preserved in the long term.

Prevalence of lower urinary tract symptoms in children with early-treated infantile-onset Pompe disease: A single-centre cross-sectional study

AIM

To evaluate lower urinary tract symptoms (LUTS) in children with infantile-onset Pompe disease (IOPD) who received early treatment.

METHODS

Pompe disease (PD), or glycogen storage disease II is a rare autosomal recessive lysosomal storage disease that affects multiple organ systems. To our knowledge, only one study has focused on the relationship between LUTS and incontinence in children with PD. This cross-sectional study was conducted from August 2019 through March 2021 and children with IOPD, who had received early and regular enzyme replacement therapy, were enrolled. Participants or their parents completed the Dysfunctional Voiding Scoring System (DVSS) questionnaire. All children underwent uroflowmetry and postvoid residual urine measurements. Fourteen children (age, 4-9 years) with IOPD were enrolled.

RESULTS

Ten patients (71.4%) had abnormal uroflow curves. In addition, results of the DVSS revealed that approximately half (42.9%) of our IOPD patients had voiding dysfunction, with urinary incontinence as the most common symptom (64.3%, 9/14). No significant correlations were found between LUTS and uroflow curves in children with IOPD.

CONCLUSIONS

The frequency of LUTS and lower urinary tract dysfunction noted on uroflowmetry should encourage pediatricians to actively identify IOPD patients with LUTS, regardless of the timing and frequency of their treatments, and refer them to a urologist for further evaluation and appropriate treatment.

Left ventricular apical aneurysm in Fabry disease: implications for clinical significance and risk stratification

Funding Acknowledgements

Type of funding sources: None.

Background

More than 50% of patients with Fabry disease (FD) present with cardiac phenotype, and left ventricular hypertrophy (LVH) is the most frequent manifestation. Among FD patients with LVH, a rare and novel presentation of left ventricular apical aneurysm (LVAA) has been reported.

Purpose

This study aimed to investigate the clinical incidence of LVAA and its impacts on prognosis among FD patients.

Methods

We retrospectively analyzed 268 FD patients at a tertiary medical center between January 2003 to September 2020. Two patients with ischemic LVAA were excluded. LVH and LVAA were confirmed either by echocardiography (Figure 1A) or cardiovascular magnetic resonance imaging (Figure 1B). The primary endpoints were a composite of heart failure (HF) hospitalization, sustained ventricular tachycardia (VT), stroke, and death. 

Results

Of 266 FD patients, there were 105 (39.5%) patients had LVH, and 11 (10.3%) of them had LVAAs (age 67.5 ± 9.5 years, 8 males [72.7%]). After a mean follow-up of 49.3 ± 34.8 months, 8 patients experienced primary endpoints, including 5 (45.5%) HF hospitalizations, 3 (27.3%) VT, 1 (9.1%) stroke, and 4 (36.4%) deaths. The risk for composite adverse events was significantly higher in patients with LVAA compared with those without (8 [72.7%] vs 17 [18.1%]), leading to significantly lower event-free survival in patients with LVAA (Log-Rank P &lt; 0.001, Figure 2). The presence of LVAA was independently associated with an increased risk of composite adverse events (hazard ratio: 3.59; confidence interval: 1.30-9.91, P = 0.01) after adjusting for age, gender, advanced HF, renal function, dyslipidemia, atrial fibrillation, left ventricular ejection fraction of &lt;40%, average E/e’, and LV mass index.

Conclusions

LVAA presents in around 10% of patients with Fabry cardiomyopathy and is strongly associated with an increased risk of adverse events. The identification of this phenotype would be useful to identify high-risk patients with Fabry cardiomyopathy, among whom more aggressive treatments may be considered. Abstract Figure. Apical aneurysm in Fabry cardiomyopathy  Abstract Figure. KM curve of composite adverse events

Airway abnormalities and pulmonary complications in long-term treated late-onset Pompe disease: Diagnostic and interventional by flexible bronchoscopy

This study evaluates the whole airway abnormalities of long-term treated late-onset Pompe disease (LOPD) patients, with interventions using the flexible bronchoscope (FB). As a retrospective study, we follow up with our five LOPD patients treated with Myozyme from 2012 to 2021 regularly, but with a focus on the whole airway abnormalities of these patients visualized through FB. The long-term clinical outcomes and relevant airway symptoms were assessed. Pulmonary function test and polysomnography were performed to evaluate the degree of respiratory compromise. All patients in the study had varying degrees of airway collapsibility, pulmonary complications, sleep apnea syndrome, and facial anomalies. Pulmonary function could preserve after Myozyme treatment, but potential deterioration thereafter. This is the first study that focuses on airway abnormalities and pulmonary complications in long-term treated LOPD patients using FB. Despite years of Myozyme treatment, we still observed airway abnormalities in these patients. In our series, the pulmonary complications seem more obvious than those observed in patients with infantile-onset Pompe disease, which might be related to the late diagnosis and treatment. We might recommend that FB could provide dynamic evaluation and interventions of airway abnormalities simultaneously. Early diagnosis of respiratory dysfunction is a critical prognostic factor of the long-term outcome of treated LOPD patients.

Fabry Disease and the Effectiveness of Enzyme Replacement Therapy (ERT) in Left Ventricular Hypertrophy (LVH) Improvement: A Review and Meta-Analysis

Background: Fabry disease is an inherited lysosomal storage disease affecting multiple organs with complications, including cardiomyopathy such as left ventricular hypertrophy (LVH). Enzyme replacement therapy (ERT) has been the main treatment for Fabry patients since 2001. However, the indications of ERT are not clearly defined. We performed a meta-analysis according to previous studies to review the benefit of ERT for LVH improvement in Fabry patients. Methods: We performed a literature search from the National Center for Biotechnology Information (NCBI) and PubMed database without restriction of years for systematic review purposes. We performed a systematic review of clinical cohort studies and trials using a pooled analysis of proportions. We calculated the pooled proportions and the confidence intervals (CI) for left ventricular mass index (LVMI) for both ERT treatment and ERT treatment-naïve groups. The results for before ERT treatment and after ERT treatment are also investigated. Results: A total of 5 cohort studies and 2 randomized controlled trials (RCTs), involving a total of 552 participants (267 on ERT treatment versus 285 on naïve treatment), met the inclusion criteria. The pooled proportions analysis showed that the difference in means of LVMI between the ERT treatment group and the ERT treatment-naïve group was -0.149 [95% CI: -0.431, 0.132]. Effect differences favored the ERT treatment group over the ERT treatment-naïve group (p = 0.034). Another analysis included 3 cohort studies and 1 RCT with 442 participants (228 on before ERT and 214 on 4 years after ERT). The pooled proportions analysis showed that the difference in means of LVMI between the before ERT treatment group and the after ERT treatment group was -0.448 [95% CI: -0.787, -0.108]. It favored the 4 years after ERT group over the before ERT group (p = 0.037). Conclusions: Based on the currently available data, our meta-analysis showed that there are beneficial effects on LVH improvement with ERT in Fabry disease patients. It is better to start ERT as soon as we have diagnoses in female carriers and atypically affected males. Further research is needed to investigate the role of ERT in LVH improvement.

Congenital hypopituitarism due to novel compound heterozygous POU1F1 gene mutation: A case report and review of the literature

Failure to thrive is one of the most common complaints in the endocrinology and genetics clinic. An 8-month-old girl with presentation of motor developmental delay, failure to thrive, and midline facial defects, with history of hypoglycemia at birth and central congenital hypothyroidism (CCH), was brought to our genetic clinic. Hormone test demonstrated combined pituitary hormone deficiency with growth hormone deficiency (GHD), central hypothyroidism, and hypoprolactinemia. Brain magnetic resonance imaging (MRI) showed anterior pituitary hypoplasia (APH), abnormal pituitary stalk, and preserved posterior pituitary lobe. Whole exome sequence (WES) identified a compound heterozygous mutation of the POU1F1 gene: c.649C>T (p.Arg217Ter) and c.662T>C (p.Ile221Thr), which are de novo mutation and inherited from mother, respectively. The patient's phenotype was consistent clinically with congenital hypopituitarism due to the POU1F1 gene mutation. Based on our literature review, this is the first report of the c.662T>C mutation, to the best of our knowledge. Our study demonstrates the power of WES for early diagnosis of congenital hypopituitarism with its relative phenotype for improving prognosis and preventing irreversible deficit.

Reduced global longitudinal strain as a marker for early detection of Fabry cardiomyopathy

AIMS

Fabry cardiomyopathy (FC) is characterized by progressive left ventricular hypertrophy (LVH). Conventional echocardiography is not sensitive in detecting preclinical FC before the development of LVH. We aim to investigate whether myocardial deformation analysis is useful to detect preclinical FC before LVH.

METHODS AND RESULTS

One hundred and sixty patients carrying mutated gene were prospectively enrolled, including 86 patients without LVH and 74 patients with LVH. Another 33 healthy individuals were also included for comparison. Standard transthoracic two-dimensional, Doppler, tissue Doppler echocardiography and deformation analysis were performed. The mean age of the overall 193 subjects was 48 ± 15 years, with 51% men. Fabry patients with LVH were older, more often to be men. They also had the worst diastolic function as evidenced by the largest left atrium, lowest E/A, and highest E/e' ratio. The global longitudinal strain (GLS) deteriorated with the development of LVH (control vs. LVH- patients vs. LVH+ patients = -21.2 ± 2.7 vs. -19.0 ± 2.9 vs. -16.5 ± 4.2%, P < 0.001). Despite similar LV systolic, diastolic function, and LV mass, LVH- Fabry patients still had a reduced GLS as well as regional longitudinal strains at mid-to-apical, anterior, and inferolateral wall when compared to healthy subjects. The basal longitudinal strain was consistently worse in male patients than in female patients, irrespective of LVH.

CONCLUSION

Reduced GLS could be a marker of early FC before the development of LVH.

Genetic basis and hematologic manifestations of sitosterolemia in a group of Turkish patients

BACKGROUND

Sitosterolemia is a rare lipid disorder caused by mutations in adenosine triphosphate-binding cassette genes (ABCG) 5 and 8.

OBJECTIVE

To evaluate the phenotypic/genotypic features of sitosterolemia in a group of Turkish patients.

METHODS

Seven probands with unexplained hematologic abnormalities and their 13 relatives were enrolled. Sterol levels were measured by gas chromatography and genetic studies were performed using Sanger sequencing. Individuals were diagnosed with sitosterolemia if they were found to have frankly elevated sitosterol level >15 μg/mL and/or pathogenic variants of the ABCG5/ABCG8.

RESULTS

The seven probands and their six relatives  were diagnosed with frank sitosterolemia, and all these patients had hematologic abnormalities. The remaining seven relatives were asymptomatic heterozygous carriers. Three novel variants in the ABCG5 gene (c.161G>A, c.1375C>T, IVS10-1G>T), one novel variant in the ABCG8 gene (c.1762G>C) and one known variant in the ABCG5 gene (c.1336 C>T) were identified. No variant was identified in one case. The mean sitosterol level was significantly higher and mean platelet count was significantly lower in patients with homozygous variants compared to heterozygous variants (p<0.05, for all). Diets low in plant sterols were recommended for 13 symptomatic cases. Four homozygotes received ezetimibe, and their splenomegaly, anemia, and thrombocytopenia completely resolved except one.

CONCLUSION

The five pathogenic variants identified in this study indicate the genetic heterogeneity of sitosterolemia in Turkish population. Patients with unexplained hematologic abnormalities (specifically macrothrombocytopenia) should have their sterol level measured as initial testing. Ezetimibe can be a good choice for sitosterolemia.

Genetic Analysis in a Taiwanese Cohort of 750 Index Patients with Clinically Diagnosed Familial Hypercholesterolemia

Aim: Familial hypercholesterolemia (FH) is underdiagnosed in most countries. The genetic heterogeneity of FH requires an algorithm to efficiently integrate genetic testing into clinical practice. We aimed to report the spectrum of genetic mutations from patients with clinically diagnosed FH in Taiwan.

Methods: Patients with LDL-C＞190 mg/dL or those with probable or definite FH according to the Taiwan Lipid Guidelines underwent genetic testing. Samples from 750 index patients from the Taiwan FH registry were screened using custom-made mass spectrometry, followed by targeted next generation sequencing (NGS) and/or multiplex ligation-dependent probe amplification (MLPA) if found negative.

Results: The mean age of the patients was 52.4±15.1 years and 40.9% were male. Mutations were detected in 445 patients (59.3%). The distribution of mutations was as follows:LDLR (n=395),APOB (n=58),PCSK9 (n=0), andABCG5 (n=3). The most common mutations wereAPOB c.10579 C＞T (p.R3527W) (12.6%),LDLR c.986 G＞A (p.C329Y) (11.5%), andLDLR c.1747 C＞T (p.H583Y) (10.8%).LDLR c.1187-10 G＞A (IVS 8-10) andAPOB c.10580 G＞A (p.R3527Q) were detected using targeted NGS in Taiwan for the first time. Four novel mutations were identified, includingLDLR c.1060＋2 T＞C (IVS 7＋2),LDLR c.1139 A＞C (p.E380A),LDLR c.1322 T＞C (p.A431T)＋c.1867 A＞G (p.I623V), and ABCG5 c.1337 G＞A (p.R447Q).

Conclusion:LDLR andAPOB, but notPCSK9, mutations were the major genetic causes of FH. Four novel mutations inLDLR orABCG5 were identified. This genetic screening method using mass spectrometry, targeted NGS, and MLPA analysis provided an efficient algorithm for genetic testing for clinically diagnosed FH in Taiwan.

Aortic regurgitation in Marfan syndrome patients who underwent prophylactic surgery: A single-center experience

BACKGROUND

Marfan syndrome is an inherited connective tissue disease that causes aortic root dilatation and dissection and requires surgical intervention. Apart from emergent surgery for aortic dissection or aortic aneurysmal rupture, prophylactic surgical intervention can also be administered, depending on the severity of aortic root dilatation. The direct relationship between surgical intervention and aortic regurgitation was seldom mentioned in previous studies.

METHODS

A retrospective cohort study was designed to determine the clinical presentations of prophylactic surgery in patients with Marfan syndrome. Between January 2009 and May 2019, 112 patients, adolescents and young adults, treated in the Department of Pediatric Cardiology of Taipei Veterans General Hospital, were enrolled. All patients' sex, body measurements, echocardiography reports, and surgical notes were collected for statistical analysis.

RESULTS

Among the participants, nine patients (8%) underwent the Bentall procedure, and the other 103 did not receive surgical intervention. The operation group had a larger aortic root size (4.89 vs 2.86 cm, p < 0.001), more dilated left ventricle (4.81 vs 4.1 cm, p = 0.002), and higher prevalence of moderate and severe aortic regurgitation (66% vs 1%, p < 0.001) than the nonoperation group.

CONCLUSION

Among adolescents and young adults with Marfan syndrome, echocardiographic presentation of aortic root dilatation, left ventricular dilatation, and significant aortic regurgitation was significantly associated with prophylactic surgical intervention. According to the study, significant aortic regurgitation should also be considered as an important indication for prophylactic surgery.

The benefits and challenges of family genetic testing in rare genetic diseases-lessons from Fabry disease

Background

Family genetic testing of patients newly diagnosed with a rare genetic disease can improve early diagnosis of family members, allowing patients to receive disease‐specific therapies when available. Fabry disease, an X‐linked lysosomal storage disorder caused by pathogenic variants in GLA, can lead to end‐stage renal disease, cardiac arrhythmias, and stroke. Diagnostic delays are common due to the rarity of the disease and non‐specificity of early symptoms. Newborn screening and screening of at‐risk populations, (e.g., patients with hypertrophic cardiomyopathy or undiagnosed nephropathies) can identify individuals with Fabry disease. Subsequent cascade genotyping of family members may disclose a greater number of affected individuals, often at younger age than they would have been diagnosed otherwise.

Methods

We conducted a literature search to identify all published data on family genetic testing for Fabry disease, and discussed these data, experts’ own experiences with family genetic testing, and the barriers to this type of screening that are present in their respective countries.

Results

There are potential barriers that make implementation of family genetic testing challenging in some countries. These include associated costs and low awareness of its importance, and cultural and societal issues. Regionally, there are barriers associated with population educational levels, national geography and infrastructures, and a lack of medical geneticists.

Conclusion

In this review, the worldwide experience of an international group of experts of Fabry disease highlights the issues faced in the family genetic testing of patients affected with rare genetic diseases.

Natural progression of cardiac features and long-term effects of enzyme replacement therapy in Taiwanese patients with mucopolysaccharidosis II

Background

Cardiac abnormalities have been observed in patients with mucopolysaccharidosis type II (MPS II). The aim of this study was to investigate the cardiac features and natural progression of Taiwanese patients with MPS II, and evaluate the impact of enzyme replacement therapy (ERT) on cardiac structure and function.

Methods

The medical records and echocardiograms of 48 Taiwanese patients with MPS II (median age, 6.9 years; age range, 0.1–27.9 years) were reviewed. The relationships between age and each echocardiographic parameter were analyzed.

Results

The mean z-scores of left ventricular mass index (LVMI), interventricular septum diameter in diastole (IVSd), left ventricular posterior wall diameter in diastole (LVPWd), and aortic diameter were 1.10, 2.70, 0.95 and 1.91, respectively. Z scores > 2 were identified in 33%, 54%, 13%, and 46% for LVMI, IVSd, LVPWd, and aortic diameter, respectively. The most prevalent cardiac valve abnormality was mitral regurgitation (MR) (56%), followed by aortic regurgitation (AR) (33%). The severity of mitral stenosis (MS), MR, aortic stenosis (AS), AR, and the existence of valvular heart disease were all positively correlated with increasing age (p < 0.01). We also compared the echocardiographic parameters between two groups: (1) 12 patients who had up to 17 years of follow-up echocardiographic data without ERT, and (2) nine patients who had up to 12 years of follow-up data with ERT. The results showed that z-score changes of LVMI significantly improved in the patients who received ERT compared to those who did not receive ERT (0.05 versus 1.52, p < 0.05). However, the severity score changes of MS, MR, AS, and AR all showed gradual progression in both groups (p > 0.05).

Conclusions

High prevalence rates of valvular heart disease and cardiac hypertrophy were observed in the MPS II patients in this study. The existence and severity of cardiac hypertrophy and valvular heart disease in these patients worsened with increasing age, reinforcing the concept of the progressive nature of this disease. ERT for MPS II appeared to be effective in stabilizing or reducing the progression of cardiac hypertrophy, but it only had a limited effect on valvulopathy.

Case Report: Anesthetic Management and Electrical Cardiometry as Intensive Hemodynamic Monitoring During Cheiloplasty in an Infant With Enzyme-Replaced Pompe Disease and Preserved Preoperative Cardiac Function

Introduction: Pompe disease is caused by deficiency of the lysosomal enzyme acid α-glucosidase, which results in cardiac and muscular complications that can jeopardize perioperative outcomes. We report a 4-month-old infant with Pompe disease receiving cheiloplasty under general anesthesia with the aid of peripheral nerve blocks and intensive hemodynamic monitoring. Case Description: This case report describes a 4-month-old full-term Taiwanese female infant who presented with left unilateral cleft lip and palate in the prenatal examination. She was diagnosed with infantile-onset Pompe disease after acidic α-glucosidase (GAA) gene sequencing. She also received enzyme replacement therapy (ERT) 15 days after birth and regular ERT every other week. Cheiloplasty was performed under general anesthesia uneventfully, and peripheral nerve blocks were adopted for analgesia. Intensive hemodynamic monitoring using electrical cardiometry technology (ICON^®) and pulse contour analysis (FloTrac system) were applied during the operation. No adverse effects were observed, and the wound healed well. Therefore, the patient was discharged 4 days after surgery. Conclusion: With the availability of ERT, severe organ dysfunction in infantile-onset Pompe disease patients is no longer common. However, moderate cardiac depression can still occur while increasing inspiratory pressure and deepening the anesthesia level despite a normal preoperative echocardiogram report. Therefore, careful, gradual titration is desirable. Furthermore, electrical cardiometry can detect hemodynamic changes more instantaneously and reliably than pulse contour analysis. In addition, we suggest taking advantage of the peripheral nerve block as a part of balanced anesthesia to alleviate the cardiac suppression caused by general anesthesia.

Aortic Root Dilatation in Taiwanese Patients with Mucopolysaccharidoses and the Long-Term Effects of Enzyme Replacement Therapy

Background: Cardiovascular abnormalities have been observed in patients with mucopolysaccharidosis (MPS) of any type, with the most documented abnormalities being valvular regurgitation and stenosis and cardiac hypertrophy. Only a few studies have focused on aortic root dilatation and the long-term effects of enzyme replacement therapy (ERT) in these patients. Methods: We reviewed echocardiograms of 125 Taiwanese MPS patients (age range, 0.1 to 19.1 years; 11 with MPS I, 49 with MPS II, 25 with MPS III, 29 with MPS IVA, and 11 with MPS VI). The aortic root diameter was measured at the sinus of Valsalva. Results: Aortic root dilatation (z score >2) was observed in 47% of the MPS patients, including 66% of MPS IV, 51% of MPS II, 45% of MPS VI, 28% of MPS III, and 27% of MPS I patients. The mean aortic root diameter z score was 2.14 (n = 125). The patients with MPS IV had the most severe aortic root dilatation with a mean aortic root diameter z score of 3.03, followed by MPS II (2.12), MPS VI (2.06), MPS III (1.68), and MPS I (1.03). The aortic root diameter z score was positively correlated with increasing age (n = 125, p < 0.01). For the patients with MPS II, III, and IV, aortic root diameter z score was also positively correlated with increasing age (p < 0.01). For 16 patients who had received ERT and had follow-up echocardiographic data (range 2.0–16.2 years), the mean aortic root diameter z score change was −0.46 compared to baseline (baseline 2.49 versus follow-up 2.03, p = 0.490). Conclusions: Aortic root dilatation was common in the patients with all types of MPS, with the most severe aortic root dilatation observed in those with MPS IV. The severity of aortic root dilatation worsened with increasing age, reinforcing the concept of the progressive nature of this disease. ERT for MPS appears to stabilize the progression of aortic root dilatation.

Diagnosis of Arboleda-Tham syndrome by whole genome sequencing in an Asian boy with severe developmental delay

Diagnosis of a 9-month-old boy brought to our genetics clinic with chief complaints of developmental delay (DD), failure to thrive, microcephaly, trunk hypotonia and hypertonia of the extremities. Multiple congenital defects but no significant syndromes or diseases were impressed. The chromosomal analysis and array comparative genomic hybridization (aCGH) revealed no significant pathogenic changes. Whole Genome Sequencing (WGS) identified a p.Glu1139fs de novo mutation of the KAT6A gene. The patient's phenotype was consistent clinically with Arboleda-Tham syndrome (ARTHS). Reviewing the literature showed that this is the first patient in Taiwan detected by WGS and that it involves a novel mutation. Comparing the highly variable clinical presentations of this syndrome with our patient, this boy's features and severe developmental defects seem to be due to a late-truncating mutation at the carboxyl end of the KAT6A protein. Our study demonstrates the power of WGS to confirm a diagnosis within 4 weeks for this rare condition.

Fabry disease and COVID-19: international expert recommendations for management based on real-world experience

The rapid spread of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 has raised questions about Fabry disease (FD) as an independent risk factor for severe COVID-19 symptoms. Available real-world data on 22 patients from an international group of healthcare providers reveals that most patients with FD experience mild-to-moderate COVID-19 symptoms with an additional complication of Fabry pain crises and transient worsening of kidney function in some cases; however, two patients over the age of 55 years with renal or cardiac disease experienced critical COVID-19 complications. These outcomes support the theory that pre-existent tissue injury and inflammation may predispose patients with more advanced FD to a more severe course of COVID-19, while less advanced FD patients do not appear to be more susceptible than the general population. Given these observed risk factors, it is best to reinforce all recommended safety precautions for individuals with advanced FD. Diagnosis of FD should not preclude providing full therapeutic and organ support as needed for patients with FD and severe or critical COVID-19, although a FD-specific safety profile review should always be conducted prior to initiating COVID-19-specific therapies. Continued specific FD therapy with enzyme replacement therapy, chaperone therapy, dialysis, renin-angiotensin blockers or participation to clinical trials during the pandemic is recommended as FD progression will only increase susceptibility to infection. In order to compile outcome data and inform best practices, an international registry for patients affected by Fabry and infected by COVID-19 should be established.

Audiological and otologic manifestations of glutaric aciduria type I

Background

Glutaric aciduria type 1 (GA-1) is a rare disease connected with speech delay and neurological deficits. However, the audiological and otologic profiles of GA-1 have not yet been fully characterized. To our knowledge, this is the largest study of comprehensive audiological and otologic evaluation in patients with GA-1 to date.

Methods

Thirteen patients diagnosed with GA-1 between January 1994 and December 2019 with audiological, radiological and genetic manifestations were retrospectively analyzed. Hearing tests were performed in all patients. MRI was performed for radiological evaluation.

Results

Hearing loss was found in 76.9% (10/13) of GA-1 patients, including slight hearing loss in 46.1% (6/13) of patients, mild hearing loss in 15.4% (2/13) of patients, and moderate hearing loss in 7.7% (1/13) of patients. Normal hearing thresholds were seen in 23% (3/13) of patients. Patients with intensive care unit (ICU) admission history showed significantly worse hearing than those without (29.17 ± 12.47 vs 13.56 ± 3.93 dB HL, 95% CI 2.92–24.70, p = 0.0176). One patient had moderate sensorineural hearing loss and a past history of acute encephalopathic crisis. No usual causative gene mutations associated with hearing loss were found in these patients. MRI showed a normal vestibulocochlear apparatus and cochlear nerve. One patient with extensive injury of the basal ganglia on MRI after acute encephalopathic crisis was found to have moderate sensorineural hearing loss. Two patients with disability scores above 5 were found to have mild to moderate hearing impairment. No obvious correlation between macrocephaly and hearing loss was found.

Conclusion

A high prevalence of hearing impairment is found in GA-1 patients. Adequate audiological evaluation is essential for these patients, especially for those after encephalopathic crises or with ICU admission history.

Survival and diagnostic age of 175 Taiwanese patients with mucopolysaccharidoses (1985-2019)

Background

Mucopolysaccharidoses (MPSs) are a group of inherited metabolic diseases, which are characterized by the accumulation of glycosaminoglycans, and eventually lead to the progressive damage of various tissues and organs.

Methods

An epidemiological study of MPS in Taiwan was performed using multiple sources. The survival and diagnostic age for different types of MPS between 1985 and 2019 were evaluated.

Results

Between 1985 and 2019, there were 175 patients diagnosed with MPS disorders in the Taiwanese population, with a median diagnostic age of 3.9 years. There were 21 (12%), 78 (45%), 33 (19%), 32 (18%) and 11 (6%) patients diagnosed with MPS I, II, III, IV and VI, respectively, with median diagnostic ages of 1.5, 3.8, 4.7, 4.5 and 3.7 years, respectively. Diagnosis of MPS patients was significantly earlier in recent decades (p < 0.01). Pilot newborn screening programs for MPS I, II, VI, IVA, and IIIB were progressively introduced in Taiwan from 2016, and 48% (16/33) of MPS patients diagnosed between 2016 and 2019 were diagnosed by one of these screening programs, with a median diagnostic age at 0.2 years. For patients born between 2016 and 2019, up to 94% (16/17) were diagnosed with MPS via the newborn screening programs. At the time of this study, 81 patients had passed away with a median age at death of 15.6 years. Age at diagnosis was positively correlated with life expectancy (p < 0.01). Life expectancy also significantly increased between 1985 and 2019, however this increase was gradual (p < 0.01).

Conclusions

The life expectancy of Taiwanese patients with MPS has improved in recent decades and patients are being diagnosed earlier. Because of the progressive nature of the disease, early diagnosis by newborn screening programs and timely implementation of early therapeutic interventions may lead to better clinical outcomes.

Allogeneic hematopoietic stem cell transplantation for treating severe lung involvement in Gaucher disease

Objective

To provide strategies for monitoring and treating severe lung involvement in Gaucher disease.

Study design

We reviewed the chart of a 5-year-old boy who developed rapidly progressive, severe infiltrative lung involvement of Gaucher disease (GD) and improved after allogeneic hematopoietic stem cell transplant (HSCT), along with other case studies reported before December 2019. He was diagnosed with GD (homozygous mutation at c.1448 T > C, p.L483P), and started receiving enzyme replacement therapy (ERT) at 17 months old. He developed respiratory distress symptoms after 45 months of ERT; chest imaging reported diffuse interstitial infiltration of the bilateral lungs and consolidations at the right lungs. Allogeneic HSCT using cells from a matched unrelated donor was performed four months upon progressive respiratory symptoms.

Results

His respiratory symptoms subsided in one month; chest imaging improvement, pulmonary function test improvement, and normalized activity of β-glucocerebrosidase were reported in three months.

Conclusion

This is the first report of a patient who received early and regular ERT but developed severe infiltrative lung involvement and recovered after allogeneic HSCT. Based on study results, we suggest regular chest imaging, even for asymptomatic patients. For patients with severe lung involvement, rapid deterioration, and unresponsive to higher ERT dosages, allogeneic HSCT should be considered.

Early indicators of disease progression in Fabry disease that may indicate the need for disease-specific treatment initiation: findings from the opinion-based PREDICT-FD modified Delphi consensus initiative

OBJECTIVES

The PRoposing Early Disease Indicators for Clinical Tracking in Fabry Disease (PREDICT-FD) initiative aimed to reach consensus among a panel of global experts on early indicators of disease progression that may justify FD-specific treatment initiation.

DESIGN AND SETTING

Anonymous feedback from panellists via online questionnaires was analysed using a modified Delphi consensus technique. Questionnaires and data were managed by an independent administrator directed by two non-voting cochairs. First, possible early indicators of renal, cardiac and central/peripheral nervous system (CNS/PNS) damage, and other disease and patient-reported indicators assessable in routine clinical practice were compiled by the cochairs and administrator from panellists' free-text responses. Second, the panel scored indicators for importance (5-point scale: 1=not important; 5=extremely important); indicators scoring ≥3 among >75% of panellists were then rated for agreement (5-point scale: 1=strongly disagree; 5=strongly agree). Indicators awarded an agreement score ≥4 by >67% of panellists achieved consensus. Finally, any panel-proposed refinements to consensus indicator definitions were adopted if >75% of panellists agreed.

RESULTS

A panel of 21 expert clinicians from 15 countries provided information from which 83 possible current indicators of damage (kidney, 15; cardiac, 15; CNS/PNS, 13; other, 16; patient reported, 24) were compiled. Of 45 indicators meeting the importance criteria, consensus was reached for 29 and consolidated as 27 indicators (kidney, 6; cardiac, 10; CNS/PNS, 2; other, 6; patient reported, 3) including: (kidney) elevated albumin:creatinine ratio, histological damage, microalbuminuria; (cardiac) markers of early systolic/diastolic dysfunction, elevated serum cardiac troponin; (CNS/PNS) neuropathic pain, gastrointestinal symptoms suggestive of gastrointestinal neuropathy; (other) pain in extremities/neuropathy, angiokeratoma; (patient-reported) febrile crises, progression of symptoms/signs. Panellists revised and approved proposed chronologies of when the consensus indicators manifest. The panel response rate was >95% at all stages.

CONCLUSIONS

PREDICT-FD captured global opinion regarding current clinical indicators that could prompt FD-specific treatment initiation earlier than is currently practised.

Cardiac manifestations in patients with classical or cardiac subtype of Fabry disease

BACKGROUND

Fabry disease (FD) is an X-linked lysosomal storage disorder engendered by a deficiency of the enzyme α-galactosidase A, leading to systemic accumulation of glycolipids. Studies have reported that the cardiac subtype of FD has a later onset and minimal extracardiac involvement. However, whether the severity of cardiac involvement differs between the classic and cardiac subtypes of FD remains unclear.

METHODS

We enrolled consecutive patients with classic FD (n = 22; median age [25th-75th percentile], 47.0 [32.75-56.25] years; men, 72.7%) as well as age- and sex-matched patients with a later-onset cardiac subtype of FD who were selected from our cohort of patients with IVS4 919G>A mutation. FD was diagnosed on the basis of clinical symptoms/signs and pedigree screening of index case, plasma α-galactosidase activity, and molecular analysis. Data on clinical manifestations, laboratory findings, and echocardiogram findings were collected before enzyme replacement treatment. Disease severity was evaluated using the Mainz Severity Score Index score.

RESULTS

All female patients demonstrated heterozygous mutations, with five, one, and four of them showing normal α-galactosidase activity, classic FD, and cardiac subtype of FD, respectively. The distributions of left ventricular performance indices and comorbidities, including hypertension, diabetes mellitus, and dyslipidemia, were similar between the two groups. Moreover, MSSI cardiovascular scores did not differ significantly between the groups (classic vs cardiac subtype, 10.0 [2.0-12.5] vs 10.5 [9.0-15.25]; p = 0.277).

CONCLUSION

Cardiac manifestations are similar between patients with classic and cardiac subtype of FD.

Cardiac Evaluation using Two-Dimensional Speckle-Tracking Echocardiography and Conventional Echocardiography in Taiwanese Patients with Mucopolysaccharidoses

Background: Mucopolysaccharidoses (MPSs) are a group of rare inherited metabolic disorders that can damage various organs, including the heart. Cardiac abnormalities have been observed in patients with all MPS types, with the most documented abnormalities being cardiac valvular regurgitation and stenosis, valvular thickening, and hypertrophic cardiomyopathy. Methods: Cardiac features of 53 Taiwanese patients with MPS (31 men and 22 women; age range 1.1–34.9 years; seven with MPS I, 16 with MPS II, nine with MPS III, 14 with MPS IVA, and seven with MPS VI) were evaluated using two-dimensional speckle-tracking echocardiography and conventional echocardiography. Results: The mean z scores of the global longitudinal strain (GLS), left ventricular mass index (LVMI), interventricular septum diameter in diastole (IVSd), left ventricular posterior wall diameter in diastole (LVPWd), and aortic diameter of the 53 patients with MPS were 1.71, 0.35, 1.66, 1.03, and 3.15, respectively. Furthermore, z scores >2 were identified in 45%, 13%, 40%, 13%, and 70% of the GLS, LVMI, IVSd, LVPWd, and aortic diameter, respectively. The most severe GLS was observed in those with MPS VI, followed by in those with MPS II and MPS I. The GLS z score was positively correlated with the LVMI z score (p < 0.01). Moreover, diastolic dysfunction (reversed ratio between early and late (atrial) ventricular filling velocity (E/A ratio < 1)) was identified in 12 patients (23%). Ejection and shortening fractions were abnormal in four (8%) and seven (13%) patients, respectively. Mitral regurgitation (MR) (92%) was the most common valvular heart disease, followed by aortic regurgitation (AR) (57%), mitral stenosis (MS) (21%), and aortic stenosis (AS) (15%). The z scores of the GLS and LVMI and severity scores of the MS, MR, AS, and AR were all positively correlated with increasing age (p < 0.05). Twenty patients (38%) had a left ventricular remodeling pattern. Conclusions: The most significant left ventricular myocardial deformation, hypertrophy and valvular heart disease were observed in the patients with MPS VI, II, and I, followed by those with MPS IV; in contrast, patients with MPS III had the mildest manifestations. Cardiac abnormalities in patients with MPS worsened with increasing age in accordance with the progressive nature of this disease.

Airway abnormalities in very early treated infantile-onset Pompe disease: A large-scale survey by flexible bronchoscopy

Early enzyme replacement therapy (ERT) improve long-term outcomes in patients with infantile-onset Pompe disease (IOPD). Our cohort of patients with IOPD at Taipei Veterans General Hospital (TVGH) joined Taiwan Pompe newborn screening program from 2008, testing more than one million newborns until 2018. By 2010, we had established rapid diagnostic strategies. Now, the average age of ERT initiation starts at an average age of <10 days-old, the earliest group in the world. However, they still presented some airway problems. We present a retrospective study focused on airway abnormalities in these patients along 8 years of observation. Fifteen patients with IOPD, who received very early treatment at a mean age of 8.94 ± 3.75 days, underwent flexible bronchoscopy (FB) for dynamic assessment of the whole airway. Long-term clinical outcomes and relevant symptoms of the upper airway were assessed. All patients in the study had varying degrees of severity of upper airway abnormalities and speech disorders. The three oldest children (Age 94, 93, and 88 months, respectively) had poor movement of the vocal cords with reduced abduction and adduction and had silent aspiration of saliva through the glottis during respiration. This is the largest cohort study presented to date about airway abnormalities in very early treated patients with IOPD patients by FB. Despite very early treatment, we observed upper airway abnormalities in these IOPD patients. In IOPD, upper airway abnormalities seem inevitable over time. We suggest early and continuous monitoring for all IOPD patients, even with early and regular treatment.

Cardio- Renal Outcomes With Long- Term Agalsidase Alfa Enzyme Replacement Therapy: A 10- Year Fabry Outcome Survey (FOS) Analysis

Purpose

Following the publication of 5-year agalsidase alfa enzyme replacement therapy (ERT) outcomes data from the Fabry Outcome Survey (FOS), 10-year data were analyzed.

Patients and methods

FOS (ClinicalTrials.gov identifier: NCT03289065) data (April 2001 to August 2018) were retrospectively analyzed. Estimated glomerular filtration rate (eGFR) and left ventricular mass indexed to height (LVMI) were analyzed after treatment start (baseline) for patients with ≥3 measurements, including baseline and year 10.

Results

Median (range) age (years) of the evaluable treated renal cohort at treatment start was 48.8 (17.9–67.3) for females (n=62), 34.4 (18.0–66.8) for males (n=90). With eGFR ≥60 mL/min/1.73 m² at baseline, mean (95% CI) rate of eGFR change (eGFR/year) over 10 years was relatively stable in females (n=52; −0.55 [−1.12, +0.01]) and slightly declined in males (n=79; −1.99 [−2.45, −1.54]). With impaired kidney function (eGFR <60 mL/min/1.73 m²) at baseline, mean (95% CI) eGFR/year was stable in females (n=10; −0.14 [−1.43, +1.15]) and slightly declined in males (n=11; −2.79 [−4.01, −1.56]) over 10 years. Median (range) age (years) of the evaluable treated cardiac cohort at treatment start was 46.7 (3.7–67.3) for females (n=34), 28.2 (4.0–54.2) for males (n=35). With left ventricular hypertrophy (LVH; LVMI >48 g/m^2.7 in females, >50 g/m^2.7 in males) at baseline, mean (95% CI) LVMI/year slightly increased over 10 years in females (n=18; +1.51 [+0.91, +2.12]) and males (n=14; +0.87 (+0.19, +1.55). Without LVH at baseline, mean (95% CI) LVMI/year was stable in females (n=16; +0.52 [−0.13, +1.17]) and males (n=21; +0.57 [+0.02, +1.13]) over 10 years.

Conclusion

Agalsidase alfa-treated patients with 10-year FOS data and preserved kidney function and/or normal LVMI at baseline remained largely stable; those with decreased kidney function or LVH at baseline experienced modest declines in renal function and/or increases in LVMI.

An At-Risk Population Screening Program for Mucopolysaccharidoses by Measuring Urinary Glycosaminoglycans in Taiwan

Background: The mucopolysaccharidoses (MPSs) are a group of rare lysosomal storage disorders characterized by the accumulation of glycosaminoglycans (GAGs) and which eventually cause progressive damage to various tissues and organs. We developed a feasible MPS screening algorithm and established a cross-specialty collaboration platform between medical geneticists and other medical specialists based on at-risk criteria to allow for an earlier confirmative diagnosis of MPS. Methods: Children (<19 years of age) with clinical signs and symptoms compatible with MPS were prospectively enrolled from pediatric clinics between July 2013 and June 2018. Urine samples were collected for a non-specific total GAG analysis using the dimethylmethylene blue (DMB) spectrophotometric method, and the quantitation of three urinary GAGs (dermatan sulfate (DS), heparan sulfate (HS), and keratan sulfate (KS)) was performed by liquid chromatography/tandem mass spectrometry (LC-MS/MS). The subjects with elevated urinary GAG levels were recalled for leukocyte enzyme activity assay and genetic testing for confirmation. Results: Among 153 subjects enrolled in this study, 13 had a confirmative diagnosis of MPS (age range, 0.6 to 10.9 years—three with MPS I, four with MPS II, five with MPS IIIB, and one with MPS IVA). The major signs and symptoms with regards to different systems recorded by pediatricians at the time of the decision to test for MPS were the musculoskeletal system (55%), followed by the neurological system (45%) and coarse facial features (39%). For these 13 patients, the median age at the diagnosis of MPS was 2.9 years. The false negative rate of urinary DMB ratio using the dye-based method for these 13 patients was 31%, including one MPS I, two MPS IIIB, and one MPS IVA. However, there were no false negative results with urinary DS, HS and KS using the MS/MS-based method. Conclusions: We established an at-risk population screening program for MPS by measuring urinary GAG fractionation biomarkers using the LC-MS/MS method. The program included medical geneticists and other medical specialists to increase awareness and enable an early diagnosis by detecting MPS at the initial onset of clinical symptoms.

Very rare condition of multiple Gaucheroma: A case report and review of the literature

Background

This study presented a 3 years old boy with Gaucher disease (GD) who was treated with enzyme replacement therapy(ERT) for 19 months and developed multiple Gaucheroma. The literature was reviewed.

Methods

The medical chart and literature were reviewed. A boy presented at the age of 15 months with anemia, thrombocytopenia, and hepatosplenomegaly. Enzyme assay and gene mutations confirmed GD. ERT was administered. When the boy was 3 years old, multiple masses were discovered from abdominal MRI and biopsy revealed Gaucheroma. We reviewed 20 GD patients with Gaucheroma and Gaucher cell infiltrated lymphadenopathies.

Conclusion

Gaucheroma is a rare condition in regularly treated GD patients. This patient showed poor response to doubled ERT doses. The imaging studies are necessary for Gaucher patients to detect Gaucheroma and determine their malignancy. Regular checkups are recommended in all GD patients even with ERT treatment, due to the possibility of having a deteriorating change, like Gaucheroma.

Functional independence of Taiwanese patients with mucopolysaccharidoses

BACKGROUND

Information on functional strengths and weaknesses of mucopolysaccharidosis (MPS) patients is important for early intervention programs and enzyme replacement therapy (ERT).

METHODS

We used the Functional Independence Measure for Children (WeeFIM) questionnaire to assess the functional skills of 63 Taiwanese MPS patients (median age, 13 years 3 months; range, 3-20 years) from January 2012 to December 2018.

RESULTS

Mean total WeeFIM score was 75.4 of a potential score of 126. Mean total WeeFIM scores of each type (MPS I, MPS II, MPS IIIB, MPS IVA, and MPS VI) were 103.8, 76.2, 41.6, 92.2, and 113.6, respectively. Mean scores for self-care, mobility, and cognition domains were 30 (maximum 56), 23 (maximum 35), and 22 (maximum 35), respectively. MPS type IIIB patients had the lowest scores in self-care, mobility, cognition, and total domains compared to other types of MPS. All patients with ERT in MPS I, II, and IVA had higher scores in self-care and mobility domains than patients without ERT. Most patients required assistance for self-care skills, especially in grooming and bathing.

CONCLUSION

MPS patients require support and supervision in self-care tasks. For cognition tasks, MPS IIIB patients also require help. This questionnaire is useful to identify the strengths and limitations of MPS patients.

Cardiac characteristics and natural progression in Taiwanese patients with mucopolysaccharidosis III

BACKGROUND

Mucopolysaccharidosis type III (MPS III), or Sanfilippo syndrome, is caused by a deficiency in one of the four enzymes involved in the lysosomal degradation of heparan sulfate. Cardiac abnormalities have been observed in patients with all types of MPS except MPS IX, however few studies have focused on cardiac alterations in patients with MPS III.

METHODS

We reviewed medical records, echocardiograms, and electrocardiograms of 26 Taiwanese patients with MPS III (five with IIIA, 20 with IIIB, and one with IIIC; 14 males and 12 females; median age, 7.4 years; age range, 1.8-26.5 years). The relationships between age and each echocardiographic parameter were analyzed.

RESULTS

Echocardiographic examinations (n = 26) revealed that 10 patients (38%) had valvular heart disease. Four (15%) and eight (31%) patients had valvular stenosis or regurgitation, respectively. The most prevalent cardiac valve abnormality was mitral regurgitation (31%), followed by aortic regurgitation (19%). However, most of the cases of valvular heart disease were mild. Three (12%), five (19%) and five (19%) patients had mitral valve prolapse, a thickened interventricular septum, and asymmetric septal hypertrophy, respectively. The severity of aortic regurgitation and the existence of valvular heart disease, aortic valve abnormalities and valvular stenosis were all positively correlated with increasing age (p < 0.05). Z scores > 2 were identified in 0, 38, 8, and 27% of left ventricular mass index, interventricular septal end-diastolic dimension, left ventricular posterior wall end-diastolic dimension, and aortic diameter, respectively. Electrocardiograms in 11 patients revealed the presence of sinus arrhythmia (n = 3), sinus bradycardia (n = 2), and sinus tachycardia (n = 1). Six patients with MPS IIIB had follow-up echocardiographic data at 1.9-18.1 years to compare with the baseline data, which showed some patients had increased thickness of the interventricular septum, as well as more patients had valvular abnormalities at follow-up.

CONCLUSIONS

Cardiac involvement in MPS III is less common and milder compared with other types of MPS. The existence of valvular heart disease, aortic valve abnormalities and valvular stenosis in the patients worsened with increasing age, reinforcing the concept of the progressive nature of this disease.

Very rare condition of multiple Gaucheroma: A case report and review of the literature

Background

This study presented a 3 years old boy with Gaucher disease (GD) who was treated with enzyme replacement therapy (ERT) for 19 months and then developed multiple Gaucheroma. Review of literature was performed simultaneously.

Methods

The medical chart and literature were reviewed. A boy presented at the age of 15 months with anemia, thrombocytopenia, and hepatosplenomegaly. GD was confirmed by enzyme assay and gene mutations. ERT was administered right after the diagnosis. When the boy was 3 years old, multiple masses were discovered during a regular checkup abdominal MRI and biopsy revealed Gaucheroma. We also reviewed 20 GD patients with Gaucheroma and Gaucher cell infiltrated lymphadenopathies.

Conclusion

Gaucheroma is a rare condition of regularly treated GD patients. This patient even showed poor response to doubled ERT doses. The imaging studies are necessary for Gaucher patients to detect Gaucheroma and determine their malignancy. Regular checkups are recommended in all GD patients even with regular treatment, due to the possibility of having deteriorating change, like Gaucheroma.

Methylmalonic acidemia/propionic acidemia - the biochemical presentation and comparing the outcome between liver transplantation versus non-liver transplantation groups

Background

Most patients with isolated methylmalonic acidemia (MMA) /propionic acidemia (PA) presenting during the neonatal period with acute metabolic distress are at risk for death and significant neurodevelopmental disability. The nationwide newborn screening for MMA/PA has been in place in Taiwan from January, 2000 and data was collected until December, 2016.

Results

During the study period, 3,155,263 newborns were screened. The overall incidence of MMA mutase type cases was 1/121,356 (n = 26), 1 cobalamin B was detected and that for PA cases (n = 4) was 1/788,816. The time of referral is 8.8 days for MMA patients, and 7.5 days for PA patients. The MMA mutase type patients have higher AST, ALT, and NH₃ values as well as a lower pH value (p < 0.05). The mean age for liver transplantation (LT) is 402 days (range from 0.6–6.7 yr) with 16 out of 20 cases (80.0%) using living donors. The mean admission length shortened from 90.6 days/year (pre-LT) to 5.3 days/year (at 3rd year post-LT) (p < 0.0005). Similarly, the tube feeding ratio decreased from 67.8 to 0.50% (p < 0.00005). The anxiety level of the caregiver was reduced from 33.4 to 27.2 after LT (p = 0.001) and the DQ/IQ performance of the patients was improved after LT from 50 to 60.1 (p = 0.07).

Conclusion

MMA/PA patients with LT do survive and have reduced admission time, reduced tube feeding and the caregiver is less anxious.

Ophthalmologic manifestations in Taiwanese patients with mucopolysaccharidoses

Background

Mucopolysaccharidoses (MPSs) are a group of rare lysosomal storage disorders characterized by the accumulation of glycosaminoglycans in various tissues and organs. Ocular problems that affect the cornea, trabecular meshwork, sclera, retina, and optic nerve are very common in these patients. However, there was limited literature focusing on comprehensive ocular findings in different types of MPS.

Methods

We retrospectively reviewed the clinical ophthalmologic features and electrodiagnostic results of 50 Taiwanese patients with a diagnosis of MPS (34 males and 16 females; age range, 1.1–34.9 years; nine with MPS I, 17 with MPS II, 17 with MPS IV, and seven with MPS VI).

Results

Among 44 patients with available data for visual acuity, 15 patients (34%) had a visual acuity of less than 0.5 (6/12) equivalent in their better eye, including 71% of those with MPS VI, 38% with MPS IV, 29% with MPS I, and 14% with MPS II. Severe corneal opacities existed in 57% of MPS VI patients and 11% of MPS I patients, compared with none for MPS II and MPS IV patients. Among 80 eyes with available data of refraction, 11 eyes (14%) had myopia (≦−0.50 D), 55 eyes (69%) had hyperopia (≧0.50 D), and 55 eyes (69%) had high astigmatism (≧1.50 D). Ocular hypertension was found in 45% (28/62) of eyes. There were 16% (14/90), 11% (10/90), 13% (12/90), 31% (27/86), and 79% (30/38) of MPS eyes with lens opacities, optic disc swelling, optic disc cupped, retinopathy, and visual pathway dysfunction, respectively. Intraocular pressure was positively correlated with the severity of corneal opacity (p < 0.01).

Conclusions

Ocular complications with significant reduction in visual acuity are common in MPS patients. Diagnostic problems may arise in these patients with severe corneal opacification, especially for those with MPS VI and MPS I.

Identification of lysosomal and extralysosomal globotriaosylceramide (Gb3) accumulations before the occurrence of typical pathological changes in the endomyocardial biopsies of Fabry disease patients

PURPOSE

Evaluation standards and treatment initiation timing have been debated for a long time, particularly for late-onset Fabry disease (FD), because of its slow progression. However, early initiation of enzyme replacement therapy (ERT) for FD could be effective in stabilizing the disease progression and potentially preventing irreversible organ damage. We aimed to examine globotriaosylceramide (Gb3) deposits in patients' endomyocardial biopsies to understand the early pathogenesis of FD cardiomyopathy.

METHODS

Immunofluorescent (IF) staining of Gb3 and lysosomal-associated membrane protein 1 (LAMP-1) was performed on endomyocardial biopsies of patients suspected of Fabry cardiomyopathy who had negative or only slight Gb3 accumulation determined by toluidine blue staining and electron microscopic examination.

RESULTS

The IF staining results revealed that all patients examined had abundant Gb3 accumulation in their cardiomyocytes, including the ones who are negative for inclusion bodies. Furthermore, we found that early Gb3 deposits were mostly confined within lysosomes, while they appeared extralysosomally at a later stage.

CONCLUSION

A significant amount of lysosomal Gb3 deposits could be detected by IF staining in cardiac tissue before the formation of inclusion bodies, suggesting the cardiomyocytes might have been experiencing cellular stress and damage early on, before the appearance of typical pathological changes of FD during the disease progression.

The relationships between urinary glycosaminoglycan levels and phenotypes of mucopolysaccharidoses

Background

The aim of this study was to use the liquid chromatography/tandem mass spectrometry (LC‐MS/MS) method to quantitate levels of three urinary glycosaminoglycans (GAGs; dermatan sulfate [DS], heparan sulfate [HS], and keratan sulfate [KS]) to help make a correct diagnosis of mucopolysaccharidosis (MPS).

Methods

We analyzed the relationships between phenotypes and levels of urinary GAGs of 79 patients with different types of MPS.

Results

The patients with mental retardation (n = 21) had significantly higher levels of HS than those without mental retardation (n = 58; 328.8 vs. 3.2 μg/ml, p < 0.001). The DS levels in the patients with hernia, hepatosplenomegaly, claw hands, coarse face, valvular heart disease, and joint stiffness were higher than those without. Twenty patients received enzyme replacement therapy (ERT) for 1–12.3 years. After ERT, the KS level decreased by 90% in the patients with MPS IVA compared to a 31% decrease in the change of dimethylmethylene blue (DMB) ratio. The DS level decreased by 79% after ERT in the patients with MPS VI compared to a 66% decrease in the change of DMB ratio.

Conclusions

The measurement of GAG fractionation biomarkers using the LC‐MS/MS method is a more sensitive and reliable tool than the DMB ratio for MPS high‐risk screening, diagnosis, subclass identification, and monitoring the efficacy of ERT.

Cardiac features and effects of enzyme replacement therapy in Taiwanese patients with Mucopolysaccharidosis IVA

BACKGROUND

Cardiac abnormalities have been observed in patients with mucopolysaccharidosis (MPS) of any type, with the most documented abnormalities being valvular heart disease and cardiac hypertrophy. However, few studies have focused on the cardiac features of MPS IVA.

METHODS

We reviewed the medical records, echocardiograms, and electrocardiograms of 32 Taiwanese patients with MPS IVA (16 males and 16 females; median age, 10.8 years; age range, 1.1 to 29.1 years) as well as the echocardiographic data of six patients who received enzyme replacement therapy (ERT) for 3-6 years.

RESULTS

Echocardiographic examinations (n = 32) revealed mean z scores of left ventricular mass index (LVMI), interventricular septum diameter in diastole (IVSd), left ventricular posterior wall diameter in diastole (LVPWd), and aortic diameter of 0.94, 2.70, 0.39, and 3.26, respectively. Z scores > 2 were identified in 25%, 50%, 29%, and 69% of the LVMI, IVSd, LVPWd, and aortic diameter values, respectively. Diastolic dysfunction [reversed ratio between early and late (atrial) ventricular filling velocity (E/A ratio < 1)] was identified in four patients (13%), however, the ejection fraction was normal (50-75%) in all of the patients. Sixteen patients (50%) had valvular heart disease and most were of mild degree. Fourteen (44%) had valvular stenosis, and 10 (31%) had regurgitation. The z scores of LVMI, IVSd, LVPWd, and aortic diameter, the severity scores of aortic stenosis and regurgitation, and the existence of a thickened interventricular septum were all positively correlated with increasing age (p < 0.05). For the 14 patients with valve thickening, the z scores of LVMI, IVSd and aortic diameter were all larger than those of the 18 patients without valve thickening (p < 0.05). For two patients who started ERT at a younger age (1.4 and 2.8 years, respectively), the z scores for LVMI, IVSd, and LVPWd all decreased after ERT.

CONCLUSIONS

A large proportion of the patients with MPS IVA had valvular heart disease and cardiac hypertrophy. Cardiac abnormalities worsened with increasing age in accordance with the progressive nature of this disease. ERT appeared to be effective in stabilizing or reducing cardiac hypertrophy, and better results may have been associated with starting ERT at a younger age.