Advantages of early replacement therapy for mucopolysaccharidosis type VI: echocardiographic follow-up of siblings

The importance of geographic and sociodemographic aspects in the characterization of mucopolysaccharidoses: a case series from Ceará state (Northeast Brazil)

Geographic and sociodemographic aspects may influence the natural history and epidemiology of mucopolysaccharidoses (MPS). The main objective in this work was to evaluate the clinical, molecular, and geographic profile of MPS in a population from Ceará (Northeast Brazil). For this, we have performed a descriptive cross-sectional study based on clinical evaluation, interviews with patients and/or family members, and review of medical records of 76 MPS patients. MPS II was the most common type, with the most affected individuals presenting missense pathogenic variants. Patients with MPS I proved to be the most severe clinical phenotype, presenting the first symptoms (mean: 7.1 months; SD = 4.5) and being diagnosed earlier (2.2 years; SD = 2.1) in comparison with the other types. In addition, we have shown that 13 individuals with MPS VI were born of consanguineous marriages in small, nearby cities, in a place where geographical isolation, consanguinity, and clusters of genetic diseases were previously reported. Ten of these individuals (at least, seven different families) presented a rare pathogenic variant in the ARSB gene, c.1143-8T > G in homozygosity, previously reported only among Iberian and South American patients. The results presented here provide a comprehensive picture of MPS in an important state of the Brazilian Northeast, a region that concentrates many risk factors for rare genetic diseases, such as endogamy, inbreeding, and reproductive isolation. We discuss the possible evolutionary processes and biosocial dynamics that can help to explain this finding in terms of population medical genetics and public health.

Metabolic Cardiomyopathies and Cardiac Defects in Inherited Disorders of Carbohydrate Metabolism: A Systematic Review

Heart failure (HF) is a progressive chronic disease that remains a primary cause of death worldwide, affecting over 64 million patients. HF can be caused by cardiomyopathies and congenital cardiac defects with monogenic etiology. The number of genes and monogenic disorders linked to development of cardiac defects is constantly growing and includes inherited metabolic disorders (IMDs). Several IMDs affecting various metabolic pathways have been reported presenting cardiomyopathies and cardiac defects. Considering the pivotal role of sugar metabolism in cardiac tissue, including energy production, nucleic acid synthesis and glycosylation, it is not surprising that an increasing number of IMDs linked to carbohydrate metabolism are described with cardiac manifestations. In this systematic review, we offer a comprehensive overview of IMDs linked to carbohydrate metabolism presenting that present with cardiomyopathies, arrhythmogenic disorders and/or structural cardiac defects. We identified 58 IMDs presenting with cardiac complications: 3 defects of sugar/sugar-linked transporters (GLUT3, GLUT10, THTR1); 2 disorders of the pentose phosphate pathway (G6PDH, TALDO); 9 diseases of glycogen metabolism (GAA, GBE1, GDE, GYG1, GYS1, LAMP2, RBCK1, PRKAG2, G6PT1); 29 congenital disorders of glycosylation (ALG3, ALG6, ALG9, ALG12, ATP6V1A, ATP6V1E1, B3GALTL, B3GAT3, COG1, COG7, DOLK, DPM3, FKRP, FKTN, GMPPB, MPDU1, NPL, PGM1, PIGA, PIGL, PIGN, PIGO, PIGT, PIGV, PMM2, POMT1, POMT2, SRD5A3, XYLT2); 15 carbohydrate-linked lysosomal storage diseases (CTSA, GBA1, GLA, GLB1, HEXB, IDUA, IDS, SGSH, NAGLU, HGSNAT, GNS, GALNS, ARSB, GUSB, ARSK). With this systematic review we aim to raise awareness about the cardiac presentations in carbohydrate-linked IMDs and draw attention to carbohydrate-linked pathogenic mechanisms that may underlie cardiac complications.

Long-term outcomes of patients with mucopolysaccharidosis VI treated with galsulfase enzyme replacement therapy since infancy

OBJECTIVE

Long-term outcomes of patients with mucopolysaccharidosis (MPS) VI treated with galsulfase enzyme replacement therapy (ERT) since infancy were evaluated.

METHODS

The study was a multicenter, prospective evaluation using data from infants with MPS VI generated during a phase 4 study (ASB-008; Clinicaltrials.govNCT00299000) and clinical data collected ≥5 years after completion of the study.

RESULTS

Parents of three subjects from ASB-008 (subjects 1, 2, and 4) provided written informed consent to participate in the follow-up study. One subject was excluded as consent was not provided. Subjects 1, 2, and 4 were aged 0.7, 0.3, and 1.1 years, respectively, at initiation of galsulfase and 10.5, 7.9, and 10.5 years, respectively, at follow-up. All subjects had classical MPS VI based on pre-treatment urinary glycosaminoglycans and the early onset of clinical manifestations. At follow-up, subject 4 had normal stature for age; subjects 1 and 2 had short stature, but height remained around the 90th percentile of growth curves for untreated classical MPS VI. Six-minute walk distance was normal for age/height in subjects 1 (550 m) and 4 (506 m), and reduced for subject 2 (340 m). Subject 2 preserved normal respiratory function, while percent predicted forced vital capacity and forced expiratory volume in 1 s decreased over time in the other subjects. Skeletal dysplasia was already apparent in all subjects at baseline and continued to progress. Cardiac valve disease showed mild progression in subject 1, mild improvement in subject 4, and remained trivial in subject 2. All subjects had considerably reduced pinch and grip strength at follow-up, but functional dexterity was relatively normal for age and there was limited impact on activities of daily living. Bruininks-Oseretsky Test of Motor Proficiency (BOT-2) results showed that subjects 2 and 4 had numerous fine and gross motor competencies. Corneal clouding progressed in all subjects, while progression of hearing impairment was variable. Liver size normalized from baseline in subjects 1 and 4, and remained normal in subject 2.

CONCLUSION

Very early and continuous ERT appears to slow down the clinical course of MPS VI, as shown by preservation of endurance, functional dexterity, and several fine and gross motor competencies after 7.7-9.8 years of treatment, and less growth impairment or progression of cardiac disease than could be expected based on the patients' classical phenotype. ERT does not seem to prevent progression of skeletal or eye disease in the long term.

Mucopolysaccharidosis type VI: case report with first neonatal presentation with ascites fetalis and rapidly progressive cardiac manifestation

BACKGROUND

The Mucopolysaccharidosis type VI (MPS VI), also known as Maroteaux-Lamy syndrome (OMIM 253200) is an autosomal recessive lysosomal disorder, caused by the deficiency of the enzyme N-acetylgalactosamine 4-sulfatase (also known as arylsulfatase B) due to mutations of the ARSB gene. Cardiologic features are well recognized, and are always present in MPS VI patients. Generally, the onset and the progression of the cardiologic symptoms are insidious, and just a few patients have developed a rapidly progressive disease. Cardiac involvement in MPS VI is a common and progressive feature. For MPS patients, cardiac evaluations are recommended every 1 to 2 years, including blood pressure measurement, electrocardiography and echocardiography. However, congestive heart failure and valvular surgical repair are not frequently seen, and if so, they are performed in adults. Here we report on an atypical MPS VI case with ascites fetalis and a rapidly progressive cardiac disease.

CASE PRESENTATION

A 6-month-old Brazilian male, only child of a Brazilian healthy non-consanguineous couple. During pregnancy, second trimester ultrasonography observed fetal ascites and bilateral hydrocele. Physical exam at 6 months-old revealed a typical gibbus deformity and MPS was suspected. Biochemical investigation revealed a diagnosis of MPS type VI, confirmed by molecular test. Baseline echocardiogram revealed discrete tricuspid regurgitation and a thickened mitral valve with posterior leaflet prolapse, causing moderate to severe regurgitation. The patient evolved with mitral insufficiency and congestive heart failure, eventually requiring surgical repair by the first year of age.

CONCLUSIONS

We report the first case of MPS VI whose manifestations started in the prenatal period with fetal ascites, with severe cardiac valvular disease that eventually required early surgical repair. Moreover, in MPS with neonatal presentation, including fetal hydrops, besides MPS I, IVA and VII, clinicians should include MPS VI in the differential diagnosis.

Enzyme Replacement Therapy Decreases Left Ventricular Mass Index in Patients with Hunter Syndrome?

Although enzyme replacement therapy (ERT) has shown benefit in improving cardiac systolic function in a murine model of cardiomyopathy associated with Hunter syndrome, few studies have analyzed its effect in humans. We evaluated the effect of ERT on patients with Hunter syndrome-related cardiomyopathy. We performed a retrospective analysis of serial transthoracic echocardiograms performed before and over the first 5 years after treatment initiation, in 14 patients with Hunter syndrome. An important cardiac remodeling occurred in all patients in this study. There was a significant reduction in left ventricular mass index from 70.88 to 26.75 g/m^2.7 (p = 0.003), with a trend towards a decrease in relative wall thickness from 0.515 at baseline to 0.370 after 5 years of enzyme therapy (p = 0.140). No differences were observed in aortic root diameter, left atrial diameter, left ventricular diastolic and systolic diameters, left ventricular ejection fraction, or myocardial performance index. Our findings demonstrate that ERT contributes to reducing left ventricular mass index in patients with Hunter syndrome.

Recommendations for the management of MPS VI: systematic evidence- and consensus-based guidance

Introduction

Mucopolysaccharidosis (MPS) VI or Maroteaux-Lamy syndrome (253200) is an autosomal recessive lysosomal storage disorder caused by deficiency in N-acetylgalactosamine-4-sulfatase (arylsulfatase B). The heterogeneity and progressive nature of MPS VI necessitates a multidisciplinary team approach and there is a need for robust guidance to achieve optimal management. This programme was convened to develop evidence-based, expert-agreed recommendations for the general principles of management, routine monitoring requirements and the use of medical and surgical interventions in patients with MPS VI.

Methods

26 international healthcare professionals from various disciplines, all with expertise in managing MPS VI, and three patient advocates formed the Steering Committee group (SC) and contributed to the development of this guidance. Members from six Patient Advocacy Groups (PAGs) acted as advisors and attended interviews to ensure representation of the patient perspective. A modified-Delphi methodology was used to demonstrate consensus among a wider group of healthcare professionals with expertise and experience managing patients with MPS VI and the manuscript has been evaluated against the validated Appraisal of Guidelines for Research and Evaluation (AGREE II) instrument by three independent reviewers.

Results

A total of 93 guidance statements were developed covering five domains: (1) general management principles; (2) recommended routine monitoring and assessments; (3) enzyme replacement therapy (ERT) and hematopoietic stem cell transplantation (HSCT); (4) interventions to support respiratory and sleep disorders; (5) anaesthetics and surgical interventions. Consensus was reached on all statements after two rounds of voting. The greatest challenges faced by patients as relayed by consultation with PAGs were deficits in endurance, dexterity, hearing, vision and respiratory function. The overall guideline AGREE II assessment score obtained for the development of the guidance was 5.3/7 (where 1 represents the lowest quality and 7 represents the highest quality of guidance).

Conclusion

This manuscript provides evidence- and consensus-based recommendations for the management of patients with MPS VI and is for use by healthcare professionals that manage the holistic care of patients with the intention to improve clinical- and patient-reported outcomes and enhance patient quality of life. It is recognised that the guidance provided represents a point in time and further research is required to address current knowledge and evidence gaps.

Electronic supplementary material

The online version of this article (10.1186/s13023-019-1080-y) contains supplementary material, which is available to authorized users.

Clinical effectiveness of enzyme replacement therapy with galsulfase in mucopolysaccharidosis type VI treatment: Systematic review

INTRODUCTION

Mucopolysaccharidosis VI is a rare disease characterized by the arylsulfatase B enzyme deficiency, which is responsible for different clinical manifestations. The treatment consists of enzyme replacement therapy with intravenous administration of galsulfase.

OBJECTIVE

Evaluate the effectiveness of the enzyme replacement therapy with galsulfase for the mucopolysaccharidosis VI treatment.

METHOD

Systematic review of observational studies. The databases of PubMed, Cochrane Library, Lilacs, and Journal of Inherited Metabolic Disease were reviewed. The selection of studies, data mining, and methodological quality assessment were independently conducted by two authors.

RESULTS

Eighteen studies fulfilled the inclusion criteria. Two studies were cohorts, one was longitudinal study, one was cross-sectional, one was a case-control, eight were case series, and five were case reports. A total of 362 participants with mucopolysaccharidosis type VI were evaluated, and 14 different outcomes related to the treatment effect were identified. Seven outcomes showed positive results, characterized by the patient survival, quality of life, respiratory function, joint mobility, physical resistance, reduction of urinary glycosaminoglycans, and growth. The hearing function and the cognitive development were stable after the treatment. Other outcomes related to the cardiac function, visual acuity, sleep apnea, and the size of the liver and spleen presented inconclusive outcomes. Concerning safety, light adverse reactions of hypersensitivity were reported.

CONCLUSION

This review provided a broader panoramic view of the outcomes related to mucopolysaccharidosis type VI. Regardless of the inherent limitations of observational studies, the outcomes indicate that the enzyme replacement therapy has a positive effect on most of the outcomes associated to the disease.

Genetic Infiltrative Cardiomyopathies

Infiltrative cardiomyopathies are characterized by abnormal accumulation or deposition of substances in cardiac tissue leading to cardiac dysfunction. These can be inherited, resulting from mutations in specific genes, which engender a diverse array of extracardiac features but overlapping cardiac phenotypes. This article provides an overview of each inherited infiltrative cardiomyopathy, describing the causative genes, the pathologic mechanisms involved, the resulting cardiac manifestations, and the therapies currently offered or being developed.

Clinical outcomes in a subpopulation of adults with Morquio A syndrome: results from a long-term extension study of elosulfase alfa

Background

This post hoc subanalysis examined outcomes in adult patients with Morquio A (mucopolysaccharidosis IVA) who received enzyme replacement therapy (ERT) with elosulfase alfa over a 120-weeks period. Patients ≥18 years of age evaluated in an open-label, long-term extension study of elosulfase alfa (modified per protocol [MPP], n = 32; intent-to-treat [ITT], n = 37; MOR-005; NCT01415427) were compared with the ≥18-year-old untreated population with 2-years follow-up from a Morquio A natural history study (n = 10; MorCAP; NCT00787995). The MOR-005 MPP population excluded patients who underwent orthopedic surgical procedures or were noncompliant with study protocol (defined as missing ≥20% of ERT infusions). No MorCAP patients underwent orthopedic surgical procedures during the relevant time period. Endurance was assessed by the 6-min walk test (6MWT) and 3-min stair climb test (3MSCT). Activities of daily living (ADLs) were assessed by the MPS Health Assessment Questionnaire (MPS HAQ).

Results

Least squares (LS) mean (SE) 6MWT distances increased by 34.9 (11.7) m (MPP) and 30.5 (10.8) m (ITT) by week 120; LS mean (SE) change in 3MSCT at week 120 was 6.7 (1.8) stairs/min (MPP) and 5.9 (1.7) stairs/min (ITT). MorCAP patients showed no improvement in 6MWT distance or 3MSCT over a similar period of time. Pulmonary function measures remained unchanged in both MOR-005 and MorCAP adults. All MPS HAQ domain scores improved in MOR-005 adults, whereas MorCAP adults had unchanged caregiver assistance and mobility outcomes and worsened self-care outcomes.

Conclusions

Long-term ERT in adult patients with Morquio A was associated with increased endurance and improvement in performance of ADLs.

Trial registration

Trial Registration NCT01415427. Name of registry: Long-Term Efficacy and Safety Extension Study of BMN 110 in Patients With Mucopolysaccharidosis IVA (Morquio A Syndrome). Registered 8 August 2011, retrospectively registered.

Electronic supplementary material

The online version of this article (doi:10.1186/s13023-017-0634-0) contains supplementary material, which is available to authorized users.

The effect of neonatal gene therapy with a gamma retroviral vector on cardiac valve disease in mucopolysaccharidosis VII dogs after a decade

Mucopolysaccharidosis VII (MPS VII) is due to deficient activity of the lysosomal enzyme β-glucuronidase (GUSB) and results in the accumulation of glycosaminoglycans (GAGs). This study determined the long-term effect of neonatal intravenous injection of a gamma retroviral vector (RV) on cardiac valve disease in MPS VII dogs. Transduced hepatocytes secreted GUSB into the blood for up to 11 years at levels similar to or greater than those achieved with enzyme replacement therapy (ERT). Valve regurgitation and thickening were scored from 0 (normal) to +4 (severely abnormal). At 1 year, untreated MPS VII dogs had mitral regurgitation, mitral valve thickening, aortic regurgitation, and aortic valve thickening scores of 2.3 ± 0.7, 2.3 ± 0.6, 1.8 ± 0.5, and 1.6 ± 0.7, respectively, which were higher than the values of 0.6 ± 0.1, 0.1 ± 0.4, 0.3 ± 0.8, and 0.1 ± 0.4, respectively, in treated MPS VII dogs. Treated MPS VII dogs maintained low aortic regurgitation and aortic valve thickening scores in their lifetime. Although mitral regurgitation and mitral valve thickening scores increased to 2.0 at ≥ 8 years of age in the treated MPS VII dogs, older normal dogs from the colony had similar scores, making it difficult to assess mitral valve disease. Older treated dogs had calcification within the mitral and the aortic valve annulus, while GUSB staining demonstrated enzyme activity within the mitral valve. We conclude that neonatal RV-mediated gene therapy reduced cardiac valve disease in MPS VII dogs for up to 11 years, and propose that neonatal initiation of ERT should have a similar effect.