Difficulties in diagnosing slowly progressive mucopolysaccharidosis VI: A case series.
ABSTRACT An Erratum for this article can be found here: http://iospress.metapress.com/content/e16437020701m0u5/?p=df8dd6709cf44367a0c0e5d917aaeddf&pi=11We describe the cases of two adult sisters recently diagnosed with the attenuated form of mucopolysaccharidosis VI (MPS VI, Maroteaux-Lamy syndrome). MPS VI is a rare, clinically heterogeneous lysosomal storage disorder that is characterized by a deficiency in the glycosaminoglycan-degrading enzyme arylsulfatase B. Both cases had been misdiagnosed for over 30 years despite the presence of several characteristics of the disease, including short stature (mild), coarse facial features, skeletal dysmorphisms, carpal tunnel syndrome, heart valve disease, and spinal cord compression, which together are suggestive of a lysosomal storage disease. Awareness about the clinical features of MPS VI should be communicated amongst treating neurologists, rheumatologists and other specialists who are involved in the healthcare decisions of these patients with presenting symptoms, so they can refer them to specialized centers for proper diagnosis and treatment.
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ABSTRACT: Mucopolysaccharidosis type VI (Maroteaux-Lamy syndrome, MPS VI, OMIM 253200) is caused by mutations in the gene coding for N-acetylgalactosamine-4-sulfatase (4-sulfatase, arylsulfatase B, ARSB, EC 188.8.131.52), a lysosomal enzyme involved in the degradation of dermatan sulfate (DS). The clinical presentation of MPS VI varies greatly with respect to age of onset and rate of disease progression. This report focuses on the attenuated form of MPS VI, which can go unrecognized for years and often presents with atypical signs or symptoms. We described a cohort of MPS VI patients (n = 4) heterozygous for the p.Y210C mutation who had a significant osteoarticular involvement at the onset of their disease and who were diagnosed years or even decades later. We have also reviewed the literature (n = 36). Two types of attenuated MPS VI phenotypes could be distinguished: osteoarticular and cardiac. The majority of MPS VI patients reported so far as relatively attenuated presented with an essentially osteoarticular phenotype associated with the p.Y210C mutation. Patients homozygous for the p.R152W mutation presented with a cardiac phenotype, which, despite fulfilling the generally used criteria for attenuated phenotype, may lead to fast disease progression and abrupt death. The knowledge of natural history and genotype-phenotype correlation may help in developing a tailored therapy potentially using enzyme replacement therapy with substrate reduction therapy or chaperones.Clinical Rheumatology 11/2013; 33(5). DOI:10.1007/s10067-013-2423-z · 1.77 Impact Factor
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ABSTRACT: Mucopolysaccharidosis IVA (MPS IVA, or Morquio A syndrome) and VI (MPS VI, or Maroteaux-Lamy syndrome) are autosomal recessive lysosomal storage disorders. Skeletal abnormalities are common initial presenting symptoms and, when recognized early, may facilitate timely diagnosis and intervention, leading to improved patient outcomes. Patients with slowly progressing disease and nonclassic phenotypes can be particularly challenging to diagnose. The objective was to describe the radiographic features of patients with a delayed diagnosis of MPS IVA or VI. This was a retrospective study. The records of 5 MPS IVA and 3 MPS VI patients with delayed diagnosis were reviewed. Radiographs were evaluated by a radiologist with special expertise in skeletal dysplasias. An important common theme in these cases was the appearance of multiple epiphyseal dysplasia (MED) with epiphyseal changes seemingly confined to the capital (proximal) femoral epiphyses. Very few patients had the skeletal features of classical dysostosis multiplex. Radiologists should appreciate the wide phenotypic variability of MPS IVA and VI. The cases presented here illustrate the importance of considering MPS in the differential diagnosis of certain skeletal dysplasias/disorders, including MED, some forms of spondylo-epiphyseal dysplasia (SED), and bilateral Perthes-like disease. It is important to combine radiographic findings with clinical information to facilitate early testing and accurate diagnosis.Skeletal Radiology 01/2014; 43(3). DOI:10.1007/s00256-013-1797-y · 1.74 Impact Factor
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ABSTRACT: Mucopolysaccharidosis VI (MPS VI, Maroteaux-Lamy syndrome) is caused by deficient activity of the enzyme, N-acetylgalactosamine-4-sulfatase, resulting in impaired degradation of the glycosaminoglycan dermatan sulfate. Patients experience a range of manifestations including joint contractures, short stature, dysostosis multiplex, coarse facial features, decreased pulmonary function, cardiac abnormalities, corneal clouding and shortened life span. Recently, clinicians from institutions in the Asia-Pacific region met to discuss the occurrence and implications of delayed diagnosis and misdiagnosis of MPS VI in the patients they have managed. Eighteen patients (44% female) were diagnosed. The most common sign presented by the patients was bone deformities in 11 patients (65%). Delays to diagnosis occurred due to the lack of or distance to diagnostic facilities for four patients (31%), alternative diagnoses for two patients (15%), and misleading symptoms experienced by two patients (15%). Several patients experienced manifestations that were subtler than would be expected and were subsequently overlooked. Several cases highlighted the unique challenges associated with diagnosing MPS VI from the perspective of different specialties and provide insights into how these patients initially present, which may help to elucidate strategies to improve the diagnosis of MPS VI. Copyright © 2015 Elsevier Inc. All rights reserved.Molecular Genetics and Metabolism 03/2015; 115(1). DOI:10.1016/j.ymgme.2015.03.005 · 2.83 Impact Factor