Ting-Rong Hsu

A large-scale nationwide newborn screening program for pompe disease in Taiwan: Towards effective diagnosis and treatment

The aim of this study was to: (a) analyze the results of a large‐scale newborn screening program for Pompe disease, and (b) establish an effective diagnostic protocol to obtain immediate, valid diagnosis of infantile‐onset Pompe disease (IOPD) to promote earlier treatment and better outcomes. In this study, 402,281 newborns were screened for Pompe disease from January 1, 2008 to May 1, 2012. Infants with low acid α‐glucosidase (GAA) activity were referred to Taipei Veterans General Hospital for diagnostic confirmation. Physical examination, biochemical parameter (creatine kinase [CK], alanine transaminase, aspartate aminotransferase, and lactate dehydrogenase), and echocardiogram assessments were performed immediately to effectively differentiate IOPD from suspected late‐onset Pompe disease (LOPD) or false‐positive cases with pseudodeficiency mutation. Six infants with IOPD all presented with hypotonia, extremely low GAA enzyme activity (≤0.5 µmol/L/hr) in initial dried blood spot analysis, high CK (≥250 U/L), and high left ventricular mass index (LVMI, ≥80 g/m2). By analyzing these parameters, IOPD was distinguished effectively and immediately from suspected LOPD and false‐positive cases. Except for the first referred case, five of the infants with IOPD received first‐time enzyme replacement therapy (ERT) within 4 hr of admission and exhibited marked improvement. Our findings indicate that certain clinical manifestations (hypotonia, high CK, enlarged LVMI, and extremely low GAA enzyme activity in initial dried blood spot analysis) can help in the rapid and effective differentiation of patients with IOPD from other patient with low GAA activity. Such differentiation allows for the early application of first‐time ERT and leads to better outcomes.

Later Onset Fabry Disease, Cardiac Damage Progress in Silence: Experience With a Highly Prevalent Mutation

BACKGROUND Recently, several studies revealed a much higher prevalence of later onset Fabry disease (FD) than previously expected. It suggested that later onset FD might present as an important hidden health issue in certain ethnic or demographic populations in the world. However, the natural history of its phenotype has not been systemically investigated, especially the cardiac involvement. OBJECTIVES The study analyzed a large-scale newborn screening program for FD to understand the natural course of later onset FD. METHODS To date, 916,383 newborns have been screened for FD in Taiwan, including more than 1,200 individuals with the common, later onset IVS4+919G>A (IVS4) mutation. Echocardiography was performed in 620 adults with the IVS4 mutation to analyze the prevalence of left ventricular hypertrophy (LVH), and gadolinium-enhanced cardiac magnetic resonance imaging was performed in 129 patients with FD, including 100 IVS4 adults. RESULTS LVH was observed in 67% of men and 32% of women older than 40 years. Imaging evidenced significant late gadolinium enhancement in 38.1% of IVS4 men and 16.7% of IVS4 women with the IVS4 mutation but without LVH. Seventeen patients underwent endomyocardial biopsies, which revealed significant globotriaosylceramide substrate accumulation in their cardiomyocytes. CONCLUSIONS Significant cardiomyocyte substrate accumulation in IVS4 patients led to severe and irreversible cardiac fibrosis before development of LVH or other significant cardiac manifestations. Thus, it might be too late to start enzyme replacement therapy after the occurrence of LVH or other significant cardiac manifestations in patients with later onset FD. This study also indicated the importance of newborn screening for early detection of the insidious, ongoing, irreversible cardiac damage in patients with later onset FD.

Very Early Treatment for Infantile-Onset Pompe Disease Contributes to Better Outcomes

OBJECTIVE To evaluate whether very early treatment in our patients would result in better clinical outcomes and to compare these data with other infantile-onset Pompe disease (IOPD) cohort studies. METHODS In this nationwide program, 669,797 newborns were screened for Pompe disease. We diagnosed IOPD in 14 of these newborns, and all were treated and followed in our hospital. RESULTS After 2010, the mean age at first enzyme-replacement therapy (ERT) was 11.92 days. Our patients had better biological, physical, and developmental outcomes and lower anti-rh acid α-glucosidase antibodies after 2 years of treatment, even compared with one group that began ERT just 10 days later than our cohort. No patient had a hearing disorder or abnormal vision. The mean age for independent walking was 11.6 ± 1.3 months, the same age as normal children. CONCLUSIONS ERT for patients with IOPD should be initiated as early as possible before irreversible damage occurs. Our results indicate that early identification of patients with IOPD allows for the very early initiation of ERT. Starting ERT even a few days earlier may lead to better patient outcomes.

Biomarkers associated with clinical manifestations in Fabry disease patients with a late-onset cardiac variant mutation.

BACKGROUND Fabry disease is a lysosomal storage disorder with an incidence of 1:1600 for the late-onset IVS4+919G>A cardiac variant mutation in Taiwan. Signs and symptoms of this cardiac variant include left ventricular hypertrophy, mitral insufficiency and/or arrhythmias. The search for biomarkers that might predict the clinical outcomes and guide treatment options is important. We thus investigated relationships between Fabry disease biomarkers (such as globotriaosylceramide (Gb3), globotriaosylsphingosine (lyso-Gb3)/related analogues) and age, gender, enzyme activity, clinical manifestations and severity of the disease in these patients. METHOD Urine and plasma biomarkers were analyzed using tandem mass spectrometry. A large cohort of 191 adult and pediatric Fabry patients carrying the IVS4+919G>A mutation was studied. Some patients were members of the same family. RESULTS Our results show that the plasma lyso-Gb3 level, and urinary analogue levels of lyso-Gb3 at m/z (+16), (+34), and (+50) adjusted for gender and age had a positive association with the left ventricular mass index, and/or the Mainz Severity Score Index. CONCLUSIONS It might thus be of particular interest to monitor children with high levels of these biomarkers, as part of a longitudinal study in order to determine if the excretion profile at a young age is predictive of the outcomes of disease severity in adulthood.

Effects of enzyme replacement therapy for cardiac-type Fabry patients with a Chinese hotspot late-onset Fabry mutation (IVS4+919G>A)

Objective Current studies of newborn screening for Fabry disease in Taiwan have revealed a remarkably high prevalence of cardiac-type Fabry disease with a Chinese hotspot late-onset Fabry mutation (IVS4+919G>A). Design Retrospective cohort study. Setting Tertiary medical centre. Participants 21 patients with cardiac-type Fabry disease (15 men and 6 women) as well as 15 patients with classic Fabry disease (4 men and 11 women) treated with biweekly intravenous infusions of agalsidase β (1 mg/kg) or agalsidase α (0.2 mg/kg) for at least 6 months. Outcome measures These data were collected at the time before enzyme replacement therapy (ERT) began and followed up after ERT for at least 6 months, including patient demographics, medical history, parameter changes of cardiac status and renal functions, plasma globotriaosylsphingosine (lyso-Gb3) and Mainz Severity Score Index. Results After 6–39 months of ERT, plasma lyso-Gb3 was found to be reduced in 89% (17/19) and 93% (14/15) of patients with cardiac-type and classic Fabry disease, respectively, which indicated an improvement of disease severity. For patients with cardiac-type Fabry disease, echocardiography revealed the reduction or stabilisation of left ventricular mass index (LVMI), the thicknesses of intraventricular septum (IVS) and left posterior wall (LPW) in 83% (15/18), 83% (15/18) and 67% (12/18) of patients, respectively, as well as 77% (10/13), 73% (11/15) and 60% (9/15) for those with classic type. Most patients showed stable renal function after ERT. There were statistically significant improvements (p<0.05) between the data at baseline and those after ERT for values of plasma lyso-Gb3, LVMI, IVS, LPW and Mainz Severity Score Index. No severe clinical events were reported during the treatment. Conclusions ERT is beneficial and appears to be safe for Taiwanese patients with cardiac-type Fabry disease, as well as for those with the classic type.

Clinical observations on enzyme replacement therapy in patients with Fabry disease and the switch from agalsidase beta to agalsidase alfa

Background: Fabry disease is an X‐linked inherited lysosomal storage disease that can be treated with the enzymes of agalsidase beta (Fabrazyme) and agalsidase alfa (Replagal). Since June 2009, viral contamination of Genzymes production facility has resulted in a worldwide shortage of agalsidase beta, leading to the switch to agalsidase alfa for patients with Fabry disease in Taiwan. Methods: The medical records were retrospectively reviewed for nine male patients with Fabry disease from the start of agalsidase beta treatment until the switch to agalsidase alfa for at least 1 year. Results: After 12–112 months of enzyme replacement therapy (ERT), decreased plasma globotriaosylsphingosine (lyso‐Gb3) was found in five out of seven patients, indicating improvement in disease severity. Among the six patients with available echocardiographic data at baseline and after ERT, all six experienced reductions of left ventricular mass index. Renal function, including microalbuminuria and estimated glomerular filtration rate, showed stability after ERT. Mainz Severity Score Index scores revealed that all nine patients remained stable at 12 months after switching to agalsidase alfa. ERT improved or stabilized cardiac status and stabilized renal function, while reducing plasma lyso‐Gb3. ERT was well tolerated, even among the three patients who had hypersensitivity reactions. Conclusion: The switch of ERT from agalsidase beta to agalsidase alfa appears to be safe after 1 year of follow‐up for Taiwanese patients with Fabry disease.

A comparison of central nervous system involvement in patients with classical Fabry disease or the later-onset subtype with the IVS4+919G>A mutation

BackgroundPatients with the later-onset IVS4+919G>A (IVS4) Fabry mutation are known to have positive central nervous system involvement compared with age- and sex-matched controls. This study compares central nervous system manifestations in patients with the IVS4 mutation or classical Fabry mutations.MethodsThis was a retrospective analysis of magnetic resonance imaging (MRI) data from Taiwanese patients enrolled in the Fabry Outcome Survey (sponsored by Shire; data extracted March 2015).ResultsTwenty-five IVS4 (19 males) and 12 (four males) classical Fabry patients underwent MRI at a median (range) age of 60.7 (45.0–70.4) and 43.0 (18.0–61.4) years, respectively. All patients received agalsidase alfa enzyme replacement therapy; two (16.7%) classical Fabry patients underwent MRI before treatment start. The pulvinar sign occurred in eight (32.0%; seven males) IVS4 and six (50.0%; three males) classical Fabry patients. Infarction occurred in eight (32.0%) IVS4 and four (33.3%) classical Fabry patients. Fazekas scores of 0, 1, 2, and 3 were found for 15 (60.0%), seven (28.0%), two (8.0%), and one (4.0%) of the IVS4 patients and for six (50.0%), four (33.3%), two (16.7%), and 0 classical Fabry patients, respectively. Abnormal height bifurcation of the basilar artery was observed in 40.0% of IVS4 and 58.3% of classical Fabry patients; abnormal laterality was observed in 4.0% of IVS4 and 16.7% of classical Fabry patients. Median (range) basilar artery diameter was 2.7 (1.4–4.0) mm in IVS4 and 3.2 (2.3–4.7) mm in classical Fabry patients (P = 0.0293); vascular stenosis was noted in 8.3% of IVS4 patients but in no classical Fabry patients.ConclusionsA similar range of MRI findings was found for both IVS4 and classical Fabry patients. Notably, basilar artery diameter was larger in classical Fabry patients than IVS4 patients.

Age at First Cardiac Symptoms in Fabry Disease: Association with a Chinese Hotspot Fabry Mutation (IVS4+919G>A), Classical Fabry Mutations, and Sex in a Taiwanese Population from the Fabry Outcome Survey (FOS)

This is a descriptive analysis of a cohort of 59 Taiwanese patients with Fabry disease and either classical Fabry or cardiac variant IVS4+919G>A (IVS4) mutations from a disease registry, the Fabry Outcome Survey (FOS; sponsored by Shire). Most of our classical Fabry patients were symptomatic and were identified upon seeking medical advice at our clinics, whereas most of our IVS4 patients attended our clinics after newborn screening identified this mutation in their grandsons. The objective was to determine differences in cardiac manifestations between patients with classical Fabry or IVS4 mutations by comparing age at onset of selected cardiac symptoms. Data were extracted in August 2013 and analyzed retrospectively. Fifty-nine Taiwanese patients (median age at extract 60.7 years [range 15.0-86.9]; n = 36 [61%] male) with proven IVS4 (n = 41 [69%]) or classical Fabry mutations (n = 18 [31%]) had available data on cardiac symptoms. Of 55 (93%) patients with reported left ventricular hypertrophy (LVH), mean [SD] age (years) at first symptom was lower in classical Fabry males (30.0 [15.1]; n = 4) than classical Fabry females (49.6 [8.9]; n = 11; p < 0.05), but not in IVS4 females (57.4 [13.7]; n = 10) compared with IVS4 males (55.9 [11.3]; n = 30). Mean age at first LVH diagnosis was significantly lower in classical Fabry males versus IVS4 males (p < 0.05). No significant difference in age at onset of arrhythmia or conductive abnormality, chest pain, or palpitations or cardiac syncope was found between the groups. The most noteworthy finding of this study is the lack of a significant gender sex difference in age at onset of cardiac symptoms in IVS4 patients.

Experiences during newborn screening for glutaric aciduria type 1: Diagnosis, treatment, genotype, phenotype, and outcomes

Background Glutaric aciduria type 1 (GA‐1) is an organic acidemia with potentially severe neurological sequelae. In Taiwan, newborn screening (NBS) for GA‐1 began in 2001, but large‐scale reporting is lacking. This study describes Taiwans largest newborn screening population to date. Methods Between 2001 and 2015, 1,490,636 newborns were screened for GA‐1. Confirmatory examinations included the carnitine loading test. Confirmed patients were treated with a low lysine diet, carnitine, and high‐energy intake during illness. Clinical, laboratory, and neuroimaging data were analyzed. Results Fourteen newborns were diagnosed with GA‐1 (incidence: 1/106,474). C5DC concentration was clearly increased after carnitine loading in the affected newborns, but not in false‐positive newborns (p = 0.004), indicating that this test is useful as an adjuvant diagnostic method. Eleven patients followed in our hospital were enrolled, namely nine NBS patients and two patients diagnosed clinically. IVS10‐2A>C was the most common mutation. Two novel mutations (T36fs and N291K) were identified. Pendular nystagmus was found in two pediatric GA‐1 patients. The corresponding pathology was optic atrophy in one patient, but remained undetermined in the other patient. The frequency of encephalopathic crisis decreased substantially following NBS. Among patients diagnosed by NBS, cognitive functioning was better among patients with good compliance than patients with poor compliance (p = 0.03). Abnormalities were detected by brain MRI including diffusion‐weighted imaging and apparent diffusion coefficient maps; these affected various brain regions at different stages of the disease. Basal ganglion injuries occurred after an encephalopathic crisis. White matter disease was prevalent among older patients, either with or without an encephalopathic crisis. Conclusion Early diagnosis by newborn screening followed by full compliance with treatment guidelines is important to a good outcome.

Cognitive Development in Infantile-Onset Pompe Disease Under Very Early Enzyme Replacement Therapy

Most patients with infantile-onset Pompe disease die in early infancy before beginning enzyme replacement therapy, which has made it difficult to evaluate the impact of Pompe disease on cognitive development. Patients with infantile-onset Pompe disease can survive with enzyme replacement therapy, and physicians can evaluate cognitive development in these patients. We established an effective newborn screening program with quick clinical diagnostic criteria. Cognitive and motor development were evaluated using the Bayley Scales of Infant and Toddler Development–Third Edition at 6, 12, and 24 months of age. The patients who were treated very early demonstrate normal cognitive development with no significant change in cognition during this period (P = .18 > .05). The cognitive development was positively correlated with motor development (r = 0.533, P = .011). The results indicated that very early enzyme replacement therapy could protect cognitive development in patients with infantile-onset Pompe disease up to 24 months of age.