Standardising clinical outcomes measures for adult clinical trials in Fabry disease: A global Delphi consensus.

BACKGROUND: Recent years have witnessed a considerable increase in clinical trials of new investigational agents for Fabry disease (FD). Several trials investigating different agents are currently in progress; however, lack of standardisation results in challenges to interpretation and comparison. To facilitate the standardisation of investigational programs, we have developed a common framework for future clinical trials in FD. METHODS AND FINDINGS: A broad consensus regarding clinical outcomes and ways to measure them was obtained via the Delphi methodology. 35 FD clinical experts from 4 continents, representing 3389 FD patients, participated in 3 rounds of Delphi procedure. The aim was to reach a consensus regarding clinical trial design, best treatment comparator, clinical outcomes, measurement of those clinical outcomes and inclusion and exclusion criteria. Consensus results of this initiative included: the selection of the adaptative clinical trial as the ideal study design and agalsidase beta as ideal comparator treatment due to its longstanding use in FD. Renal and cardiac outcomes, such as glomerular filtration rate, proteinuria and left ventricular mass index, were prioritised, whereas neurological outcomes including cerebrovascular and white matter lesions were dismissed as a primary or secondary outcome measure. Besides, there was a consensus regarding the importance of patient-related outcomes such as general quality of life, pain, and gastrointestinal symptoms. Also, unity about lysoGb3 and Gb3 tissue deposits as useful surrogate markers of the disease was obtained. The group recognised that cardiac T1 mapping still has potential but requires further development before its widespread introduction in clinical trials. Finally, patients with end-stage renal disease or renal transplant should be excluded unless a particular group for them is created inside the clinical trial. CONCLUSION: This consensus will help to shape the future of clinical trials in FD. We note that the FDA has, coincidentally, recently published draft guidelines on clinical trials in FD and welcome this contribution.

Evidence for inflammasome activation in the brain of mucopolysaccharidosis type II mice.

Hunter syndrome or mucopolysaccharidosis type II (MPS II) is an X-linked recessive disease caused by the deficiency of iduronate 2-sulfatase (IDS), leading to storage of undegraded heparan and dermatan sulfate. Patients with the severe form present neurological abnormalities, but the mechanisms of such alterations are unknown. Here, we hypothesized that the undegraded substances found in this disease could be recognized as damage-associated molecular patterns (DAMPS), leading to activation of the inflammasome. Brains from 2 and 5 months normal and MPS II mice were studied. We observed an increase in cathepsin B activity in the brain tissue and leakage of this enzyme from the lysosome to the cytoplasm in a MPS II neuronal cell line, which is a known activator of the inflammasome. Furthermore, Caspase-1 activity and IL-1-beta levels were elevated at 5 months, confirming that this pathway is indeed altered. Our results suggest that undegraded GAG activate the inflammasome pathway in MPS II and future studies could focus on blocking such pathway to better understand the role of this process to the pathogenesis of MPS II.

Universal newborn screening: A roadmap for action.

Newborn screening (NBS) prevents morbidity and mortality by screening babies for selected disorders in the first days of life so that early diagnosis and treatment can be initiated. Congenital disorders impact an estimated 8 million or 6% of annual births worldwide, and of the top five that contribute 25% to the global burden of these disorders, three can be identified and managed by NBS. There are determined pockets of activity in Latin America, Sub-Saharan Africa, and the Asia Pacific region, where partnerships among government, non-governmental organizations, academia, the private sector and civil society are developing novel NBS programs that are both saving lives and preventing disability in those who survive.

Worldwide distribution of common IDUA pathogenic variants.

Mucopolysaccharidosis type I (MPS I) is a rare disorder caused by deleterious sequence variants in the α-L-iduronidase (IDUA) gene. More than 200 pathogenic variants have been described so far, but their frequencies have not yet been analyzed on a worldwide scale. To address this, we analyzed the genotypes of MPS I patients from 35 published studies papers. The most common pathogenic variant observed was p.Trp402Ter. With frequencies of up to 63%, it was the major allele in most European countries, America and Australia. The variant p.Gln70Ter was also frequent; it was found mainly in Northern and Eastern Europe. The most frequent variant in North African countries was p.Pro533Arg; in Morocco, it represented more than 90% of mutant alleles. Variants observed in East Asians were not found in Western populations, including c.1190-1G>A, p.Ala79Val, p.Leu346Arg and c.613_617dupTGCTC. Conversely, p.Trp402Ter and p.Pro533Arg were not found in patients from East Asia. In conclusion, the most common pathogenic IDUA variant in MPS I patients are p.Trp402Ter, p.Gln70Ter and p.Pro533Arg. Knowledge about the genetic background of MPS I for each population is essential when developing new genotype-targeted therapies, as well as to enable faster genetic analysis and improve patient management.

p.L18P: a novel IDUA mutation that causes a distinct attenuated phenotype in mucopolysaccharidosis type I patients.

Mucopolysaccharidosis type I is a rare autosomal recessive disorder caused by deficiency of α-l-iduronidase (IDUA) which leads to a wide spectrum of clinical severity. Here, we describe the case of four male patients who present the previously undescribed p.L18P mutation. Patient 1 (p.L18P/p.L18P) presents, despite multiple joint contractures, an attenuated phenotype. Patient 2 (p.L18P/p.W402X) was diagnosed at 4 years of age with bone dysplasia, coarse facies, limited mobility, claw hands and underwent bilateral carpal tunnel surgery at 6 years of age. Patients 3 and 4 (both p.L18P/p.L18P) are brothers. Patient 3 was diagnosed at 4 years of age, when presented claw hands, lower limb and shoulder pain, restricted articular movement and bilateral carpal tunnel syndrome. Patient 4 was diagnosed at 17 months of age when presented lower limb pain at night, respiratory allergy and repeated upper airways infections. Bioinformatics analysis indicates that p.L18P mutation reduces the signal peptide to 25 amino acids and alters its secondary structure. In conclusion, we report a new IDUA variant that alters the structure of the signal peptide, which likely impairs transport to lysosomes. Moreover, it leads to a distinct attenuated phenotype with mainly bone and cartilage symptoms, without visceromegalies, heart disease, or cognitive impairment.

In vitro effect of genistein on DNA damage in leukocytes from mucopolysaccharidosis IVA patients.

Mucopolysaccharidosis IVA is a lysosomal storage disorder leading to an increase in glycosaminoglycans storage. Genistein is an isoflavone capable to inhibit glycosaminoglycans production. The objective of this study was to analyze the in vitro effect of different concentrations of genistein on DNA injury in mucopolysaccharidosis IVA patients. The lower concentration tested (10 µM) showed a significant increase on DNA injury in vitro, although higher concentrations (30 µM and 50 µM) showed higher DNA damage.

Mucopolysaccharidosis type II: identification of 30 novel mutations among Latin American patients.

In this study, 103 unrelated South-American patients with mucopolysaccharidosis type II (MPS II) were investigated aiming at the identification of iduronate-2-sulfatase (IDS) disease causing mutations and the possibility of some insights on the genotype-phenotype correlation The strategy used for genotyping involved the identification of the previously reported inversion/disruption of the IDS gene by PCR and screening for other mutations by PCR/SSCP. The exons with altered mobility on SSCP were sequenced, as well as all the exons of patients with no SSCP alteration. By using this strategy, we were able to find the pathogenic mutation in all patients. Alterations such as inversion/disruption and partial/total deletions of the IDS gene were found in 20/103 (19%) patients. Small insertions/deletions/indels (<22 bp) and point mutations were identified in 83/103 (88%) patients, including 30 novel mutations; except for a higher frequency of small duplications in relation to small deletions, the frequencies of major and minor alterations found in our sample are in accordance with those described in the literature.

Assay of heparan-N-sulfamidase in dried leukocytes impregnated in filter paper: a new tool for the identification of mucopolisaccharidosis IIIA and potentially other lysosomal disorders.

Diagnosis of lysosomal storage disorders (LSDs) is mainly based on specific enzyme assays in leucocytes. Dried blood spots have also been used as sample for the enzyme assays. However, some lysosomal enzymes such as heparan-N-sulfamidase (HNS) and others cannot be assayed by this material. We developed an assay for HNS using dried leukocytes impregnated in filter paper (DLFP) as source of enzyme, and the results allowed the correct identification of Mucopolisaccharidosis IIIA. From this proof of concept we predict that the assay of lysosomal enzymes in DLFP samples, which still needs further development, could be a useful tool for the diagnosis of LSDs, especially in regions where transportation of liquid blood samples in appropriate conditions for long distances and/or across country borders is challenging.

A Phase 2 study of migalastat hydrochloride in females with Fabry disease: selection of population, safety and pharmacodynamic effects.

BACKGROUND: Fabry disease (FD) is a genetic disorder resulting from deficiency of the lysosomal enzyme α-galactosidase A (α-Gal A) which leads to globotriaosylceramide (GL-3) accumulation in multiple tissues. We report on the safety and pharmacodynamics of migalastat hydrochloride, an investigational pharmacological chaperone given orally every other day (QOD) to females with FD. METHODS: This was an open-label, uncontrolled, Phase 2 study of 12 weeks with extension to 48 weeks in nine females with FD. Doses of 50mg, 150 mg and 250 mg were given QOD. At multiple time points, α-Gal A activity and GL-3 levels were quantified in blood cells, kidney and skin. GL-3 levels were also evaluated through skin and renal histology. Each individual GLA mutation was retrospectively categorized as being amenable or not to migalastat HCl based on an in vitro α-Gal A transfection assay developed in human embryonic kidney (HEK)-293 cells. RESULTS: Migalastat HCl was generally well tolerated. Patients with amenable mutations seem to demonstrate greater pharmacodynamic response to migalastat HCl compared to patients with non-amenable mutations. The greatest declines in urine GL-3 were observed in the three patients with amenable GLA mutations that were treated with 150 or 250 mg migalastat HCl QOD. Additionally, these three patients all demonstrated decreases in GL-3 inclusions in kidney peri-tubular capillaries. CONCLUSIONS: Migalastat HCl is a candidate oral pharmacological chaperone that provides a potential novel genotype-specific treatment for FD. Treatment resulted in GL-3 substrate decrease in female patients with amenable GLA mutations. Phase 3 studies are ongoing.

Enzyme replacement therapy for mucopolysaccharidosis VI: long-term cardiac effects of galsulfase (Naglazyme®) therapy.

Characteristic cardiac valve abnormalities and left ventricular hypertrophy are present in untreated patients with mucopolysaccharidosis type VI (MPS VI). Cardiac ultrasound was performed to investigate these findings in subjects during long-term enzyme replacement therapy (ERT) with recombinant human arylsulfatase B (rhASB, rhN-acetylgalactosamine 4-sulfatase, galsulfase, Naglazyme®). Studies were conducted in 54 subjects before ERT was begun and at specific intervals for up to 96 weeks of weekly infusions of rhASB at 1 mg/kg during phase 1/2, phase 2, and phase 3 trials of rhASB. At baseline, mitral and aortic valve obstruction was present and was significantly greater in those ≥12 years of age. Mild mitral and trace aortic regurgitation were present, the former being significantly greater in those <12 years. Left ventricular hypertrophy, with averaged z-scores ranging from 1.6-1.9 SD greater than normal, was present for ages both <12 and ≥12 years. After 96 weeks of ERT, ventricular septal hypertrophy regressed in those <12 years. For those ≥12 years, septal hypertrophy was unchanged, and aortic regurgitation increased statistically but not physiologically. Obstructive gradients across mitral and aortic valves remained unchanged. The results suggest that long-term ERT is effective in reducing intraventricular septal hypertrophy and preventing progression of cardiac valve abnormalities when administered to those <12 years of age.

Delivering genetic education and genetic counseling for rare diseases in rural Brazil.

Brazil is the largest country in Latin America, with an ethnically diverse, Portuguese-speaking and predominantly Roman Catholic population of some 194 million. Universal health care is provided under the Federal Unified Health System (Sistema Único de Saúde) but, as in many other middle and low income countries, access to medical genetics services is limited in rural and remote regions of the country. Since there is no formally recognized Genetic Counseling profession, genetic counseling is provided by physicians, trained either in medical genetics or a related clinical discipline. A comprehensive medical genetics program has been established in Monte Santo, an inland rural community located in the state of Bahia in Northeast Brazil, with high prevalences of a number of autosomal recessive genetic disorders, including non-syndromic deafness, phenyketonuria, congenital hypothyroidism and mucopolysaccharidosis VI (Maroteaux-Lamy syndrome). Genetic education, counseling and treatment are locally provided, with a neonatal screening program for MPSVI currently under trial.

Expert recommendations for the laboratory diagnosis of MPS VI.

Mucopolysaccharidosis VI (MPS VI) is a lysosomal storage disease caused by a deficiency of N-acetylgalactosamine 4-sulfatase (arylsulfatase B, ASB). This enzyme is required for the degradation of dermatan sulfate. In its absence, dermatan sulfate accumulates in cells and is excreted in large quantities in urine. Specific therapeutic intervention is available; however, accurate and timely diagnosis is crucial for maximal benefit. To better understand the current practices for diagnosis and to establish diagnostic guidelines, an international MPS VI laboratory diagnostics scientific summit was held in February of 2011 in Miami, Florida. The various steps in the diagnosis of MPS VI were discussed including urinary glycosaminoglycan (uGAG) analysis, enzyme activity analysis, and molecular analysis. The following conclusions were reached. Dilute urine samples pose a significant problem for uGAG analysis and MPS VI patients can be missed by quantitative uGAG testing alone as dermatan sulfate may not always be excreted in large quantities. Enzyme activity analysis is universally acknowledged as a key component of diagnosis; however, several caveats must be considered and the appropriate use of reference enzymes is essential. Molecular analysis supports enzyme activity test results and is essential for carrier testing, subsequent genetic counseling, and prenatal testing. Overall the expert panel recommends caution in the use of uGAG screening alone to rule out or confirm the diagnosis of MPS VI and acknowledges enzyme activity analysis as a critical component of diagnosis. Measurement of another sulfatase enzyme to exclude multiple sulfatase deficiency was recommended prior to the initiation of therapy. When feasible, the use of molecular testing as part of the diagnosis is encouraged. A diagnostic algorithm for MPS VI is provided.

High proportion of mannosidosis and fucosidosis among lysosomal storage diseases in Cuba.

Although lysosomal storage disorders (LSDs) are considered individually rare, as a group they present a non-negligible frequency. Few studies have been made of populational occurrence of LSDs; they have been conducted predominantly on Caucasian populations. We studied the occurrence of LSDs in Cuba. Data from individuals who had been referred to the Institute of Neurology and Neurosurgery in Havana from hospitals all over the country between January 1990 and December 2005 were analyzed. This institute was the only laboratory to provide enzyme-based diagnostic testing for 19 LSDs in Cuba during this period. Occurrence rates were calculated by dividing the number of postnatal diagnoses by the number of births during the study period. The combined occurrence of LSDs in Cuba was 5.6 per 100,000, lower than that reported in other studies conducted on Caucasian populations. The most frequent individual LSDs were: mucopolysaccharidosis type I (1.01 per 100,000) and, surprisingly, alpha-mannosidosis (0.72 per 100,000) and fucosidosis (0.62 per 100,000). These findings may be related to specific genetic characteristics and admixture of the Cuban population. This is the first comprehensive study of the occurrence of LSDs in Cuba. We conclude that the epidemiology of these diseases can vary regionally, and we stress the need for similar surveys in other Latin American countries.

Enzyme replacement therapy with agalsidase alfa in patients with Fabry's disease: an analysis of registry data.

BACKGROUND: We analysed 5-year treatment with agalsidase alfa enzyme replacement therapy in patients with Fabry's disease who were enrolled in the Fabry Outcome Survey observational database (FOS). METHODS: Baseline and 5-year data were available for up to 181 adults (126 men) in FOS. Serial data for cardiac mass and function, renal function, pain, and quality of life were assessed. Safety and sensitivity analyses were done in patients with baseline and at least one relevant follow-up measurement during the 5 years (n=555 and n=475, respectively). FINDINGS: In patients with baseline cardiac hypertrophy, treatment resulted in a sustained reduction in left ventricular mass (LVM) index after 5 years (from 71.4 [SD 22.5] g/m(2.7) to 64.1 [18.7] g/m(2.7), p=0.0111) and a significant increase in midwall fractional shortening (MFS) from 14.3% (2.3) to 16.0% (3.8) after 3 years (p=0.02). In patients without baseline hypertrophy, LVM index and MFS remained stable. Mean yearly fall in estimated glomerular filtration rate versus baseline after 5 years of enzyme replacement therapy was -3.17 mL/min per 1.73 m(2) for men and -0.89 mL/min per 1.73 m(2) for women. Average pain, measured by Brief Pain Inventory score, improved significantly, from 3.7 (2.3) at baseline to 2.5 (2.4) after 5 years (p=0.0023). Quality of life, measured by deviation scores from normal EuroQol values, improved significantly, from -0.24 (0.3) at baseline to -0.17 (0.3) after 5 years (p=0.0483). Findings were confirmed by sensitivity analysis. No unexpected safety concerns were identified. INTERPRETATION: By comparison with historical natural history data for patients with Fabry's disease who were not treated with enzyme replacement therapy, long-term treatment with agalsidase alfa leads to substantial and sustained clinical benefits. FUNDING: Shire Human Genetic Therapies AB.

Does geographical location influence the phenotype of Fabry disease in women in Europe?

This study examines the relationship between phenotype and geographical location of patients with Fabry disease in Europe. Data were taken from patients enrolled in the Fabry Outcome Survey (FOS), as of October 2007. A modified version of the Mainz Severity Score Index (FOS-MSSI) was used to classify patients according to the severity of disease. European patients were grouped depending on country of residence (northern or southern European countries). Results are presented from 762 patients enrolled in FOS in Europe (357 men and 405 women); 66% lived in northern and 34% in southern countries. Median age at onset of symptoms of Fabry disease was similar in both sexes. No differences in disease severity were seen among men, according to place of residence; however, women living in northern countries had higher severity scores (p < 0.001) than those in southern countries. In men and women, FOS-MSSI scores increased with age, irrespective of place of residence. The results suggest that expression of different phenotypic features in Fabry disease in women living in Europe may be influenced by extra-genetic or epigenetic factors. These factors might be related to dietary or environmental influences that differ according to the patient's country of residence.

Natural course of Fabry disease: changing pattern of causes of death in FOS - Fabry Outcome Survey.

BACKGROUND: Fabry disease is a rare X-linked lysosomal storage disorder characterised by severe multisystemic involvement that leads to major organ failure and premature death in affected men and women. Over the past 7 years, the Fabry Outcome Survey (FOS) has collected data on the natural history of Fabry disease, and the long-term efficacy and safety of enzyme-replacement therapy. This paper provides an update on the first analysis of FOS data. DESIGN: Baseline data on clinical manifestations and causes of death in a cohort of 1453 patients (699 male, 754 female) from 19 countries worldwide were analysed. Causes of death of affected relatives were analysed separately. RESULTS: The most frequently reported signs and symptoms of Fabry disease were neurological. Cardiac, ocular, gastrointestinal, dermatological, auditory and renal manifestations were also common. The principal causes of death among 181 affected relatives of patients in FOS (most of whom had died before 2001) were renal failure in males (42%) and cerebrovascular disease in females (25%). In contrast, of the 42 patients enrolled in FOS whose deaths were reported between 2001 and 2007, cardiac disease was the main cause of death in both male (34%) and female (57%) patients. CONCLUSION: These data suggest that the importance of renal disease as a cause of death in patients with Fabry disease is decreasing while the importance of cardiac disease is increasing. This pattern probably reflects improvements in the management of renal disease in patients with Fabry disease.

Angiokeratoma: a cutaneous marker of Fabry's disease.

The initial symptoms of Fabry's disease (FD) may seem harmless and may delay its diagnosis. A survey and screening for FD were performed on men with biopsy-proven angiokeratoma and some of their relatives (n = 29). Three patients were identified. Dermatologists should be aware of this prominent early feature and investigate unexplained cutaneous vascular lesions to detect FD.

The effect of Mycoplasma and mycoplasma removal agent on the hydrolase activity in fibroblasts of patients with lysosomal diseases.

This study was designed to evaluate the effect of mycoplasma contamination on acid hydrolase activity and the action of the mycoplasma removal agent (MRA), in cultures of human fibroblasts from individuals with lysosomal diseases. For this purpose, we measured the activity of the b-galactosidase, arylsulphatase B (ASB), hexosaminidase A and a-glucosidase enzymes. The activity of the above mentioned enzymes in fibroblasts contaminated by mycoplasma was measured before and after the addition of the MRA. The results were then compared to the enzymatic activity in contamination-free cultures. Only the ASB enzyme showed significant alteration in activity both in the presence of mycoplasma and MRA. The remaining enzymes did not suffer significant interference by the presence of the two agents. Of the four enzymes tested, three did not suffer significant alterations by the presence of the mycoplasma nor from the MRA. However, the activity measured in the ASB enzyme increased significantly in the presence of mycoplasma and MRA and could lead to a doubtful diagnosis. Therefore, we suggest that contamination should be prevented by using aseptic techniques as well as the MRA in those fibroblast cultures that cannot be discarded.

Mortality and cause of death in mucopolysaccharidosis type II-a historical review based on data from the Hunter Outcome Survey (HOS).

Mucopolysaccharidosis type II (MPS II or Hunter syndrome) is a progressive, multisystemic disease caused by a deficiency of iduronate-2-sulfatase. Patients with the severe form of the disease have cognitive impairment and typically die in the second decade of life. Patients with the less severe form do not experience significant cognitive involvement and may survive until the fifth or sixth decade of life. We studied the relationship of both severity of MPS II and the time period in which patients died with age at death in 129 patients for whom data were entered retrospectively into HOS (Hunter Outcome Survey), the only large-scale, multinational observational study of patients with MPS II. Median age at death was significantly lower in patients with cognitive involvement compared with those without cognitive involvement (11.7 versus 14.1 years; p = 0.024). These data indicate that cognitive involvement is indicative of more severe disease and lower life expectancy in patients with MPS II. Median age at death was significantly lower in patients who died in or before 1985 compared with those who died after 1985 (11.3 versus 14.1 years; p alpha 0.001). The difference in age at death between patients dying in or before, relative to after, the selected cut-off date of 1985 may reflect improvements in patient identification, care and management over the past two decades. Data from patients who died after 1985 could serve as a control in analyses of the effects of enzyme replacement therapy with idursulfase on mortality in patients with MPS II.