Mucopolysaccharidoses:
The mucopolysaccharidoses (MPS)
are a group of inherited, progressive, lysosomal disorders due to
deficiencies in various enzymes involved in the lysosomal degradation of
cellular glycosaminoglycans (GAG).
The mucopolysaccharides that accumulate
in the cells include heparan sulfate, dermatan sulfate, keratan sulfate,
and chondroitin sulfate.
The
mucopolysaccharidoses have a spectrum of systemic manifestations,
including airway and respiratory compromise, skeletal deformities,
intellectual and neurological impairment, cardiac abnormalities, and
gastrointestinal problems. Ocular manifestations are common in the
mucopolysaccharidoses and may result in significant visual
impairment. Corneal opacification of varying severity is frequently
seen, as well as retinopathy, optic nerve swelling and atrophy, ocular
hypertension, and glaucoma.
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Mucopolysaccharidosis. A case report of Morquio's type-A disease
(MPS IV-A). Minerva Stomatol.
1992 Nov;41(11):527-33.
The
mucopolysaccharidosis represent a broad spectrum of disorders due to
the deficiency of one of a group of enzymes which degrade three
classes of mucopolysaccharides: heparan sulfate, dermatan-sulfate
and keratan sulfate. The general phenotype includes coarse facies,
corneal clouding, hepatosplenomegaly, joint stiffness, hernias,
dysostosis multiplex, mucopolysaccharides excretion in the urine and
metachromatic staining in peripheral leukocytes and bone marrow.
Various components of the MPS phenotype are also found in the
mucolipidoses, glycoprotein storage diseases. Detailed clinical and
radiologic evaluation and identification of the type of MPS excreted
in the urine help to narrow the diagnosis possibilities. Definitive
diagnosis requires assay of specific enzymes in various tissues such
as cultured skin fibroblasts. For the moment there are 14 types of
known mucopolysaccharidoses, including several subtypes. They are
classified into Hurler's syndrome (MPS I-H); Scheie's syndrome (MPS
I-S); Hurler-Scheie's syndrome (MPS I-H/S); Hunter's syndrome A, B
(MPS II-A, B); Sanfilippo's syndrome A,B,C,D (MPS II-A,B,C,D);
Morquio's syndrome A,B,C (MSP IV-A,B,C); Maroteaux-Lamy's syndrome
(MPS VI) and Sly's syndrome MPS VII). The mucopolysaccharidosis
incidence is around 0.04-0.3% of the newborn and they are 1.5% of
all congenital disorders. All mucopolysaccharidosis are autosomal
recessive disorders, except for Hunter's syndrome that is X-linked
and recessive. Patient suffering of MPS, usually, don't show
clinical sign from their birth in fact they develop later their
characteristics. The average surviving of this patients is around
20-30 years old, and the exitus is due to cardiac failure or to
infections to the gastrointestinal tract or to instability of
atlantoaxial joint. |
Histologically, affected cells are
distended with clear cytoplasm (balloon cells) that contains
PAS-positive material.
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Light and electron microscopic features of the liver in
mucopolysaccharidosis.
Hum Pathol. 1994
Mar;25(3):276-86.
The
mucopolysaccharidosis (MPS) diseases lead to the accumulation of
glycosaminoglycan in many tissues. In this study 19 MPS I, one MPS
II, five MPS III, and two MPS VI patients underwent liver biopsy for
light and electron microscopic examination. Electron microscopy was
performed for all 27 specimens. Twenty-six specimens were studied by
light microscopy, and the slides were stained with colloidal iron
and alcian blue in 26 and six biopsy specimens, respectively. By
hematoxylin-eosin stain 20 of 26 cases showed hepatocellular
dilatation with rarefaction of the cytoplasm; the Kupffer cells were
unremarkable. Twenty-four and 25 of the 26 biopsy specimens showed
substantial colloidal iron staining of hepatocytes and Kupffer
cells, respectively. The six biopsy specimens prepared with alcian
blue stain showed no reactivity of any cell type. Electron
microscopy revealed characteristic membrane-bound inclusions within
the hepatocytes and Kupffer cells of all 27 biopsy specimens. Of 19
cases in which Ito cells were identified, 18 included cells
containing similar inclusions. Twenty of 27 biopsy specimens also
demonstrated the hepatocellular accumulation of lipid droplets.
Although there were no absolute distinguishing features among the
various MPS diseases, the two MPS VI cases showed glycosaminoglycan
inclusions that were fewer in number, smaller, and contained more
abundant lipofusion than those associated with the other MPS types. |
Accumulated mucopolysaccharides are found
in many cell types, including mononuclear phagocytic cells (giving rise
to hepatosplenomegaly), fibroblasts throughout the body, endothelial
cells and intimal smooth muscle cells (giving rise to narrowing of
coronary arteries); and neurons.
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Clinical and laboratorial study of 19 cases of mucopoly-
saccharidoses.Rev
Hosp Clin Fac Med Sao Paulo.2000;55(6):213-8.
The
mucopolysaccharidoses (MPS) are a heterogeneous group of inborn
errors of lysosomal glycosaminoglycan (GAG) metabolism. The
importance of this group of disorders among the inborn errors of
metabolism led us to report 19 cases. METHOD: We performed clinical,
radiological, and biochemical evaluations of the suspected patients,
which allowed us to establish a definite diagnosis in 19 cases.
RESULTS: Not all patients showed increased GAG levels in urine;
enzyme assays should be performed in all cases with strong clinical
suspicion. The diagnosis was made on average at the age of 48
months, and the 19 MPS cases, after a full clinical, radiological,
and biochemical study, were classified as follows: Hurler - MPS I (1
case); Hunter - MPS II (2 cases); Sanfilippo - MPS III (2 cases);
Morquio - MPS IV (4 cases); Maroteaux-Lamy - MPS VI (9 cases); and
Sly - MPS VII (1 case). DISCUSSION: The high relative frequency of
Maroteaux-Lamy disease contrasts with most reports in the literature
and could express a population variability. |
Several clinical variants of MPS
have been described
according to enzyme
defect and systemic manifestations and include MPS IH (Hurler), MPS IS (Scheie),
MPS IH/S (Hurler/Sheie), MPS II (Hunter), MPS III (Sanfilippo), MPS IV (Morquio),
MPS VI (Maroteaux-Lamy), MPS VII (Sly) and MPS IX (Natowicz).
Hurler's syndrome,
also known as mucopolysaccharidosis I (MPS I), is a
rare condition inherited as an autosomal recessive trait. It is caused
by a deficiency in alpha-L-iduronidase, an enzyme that participates in
the degradation of the glycosaminoglycans (GAGs) heparin sulphate and
dermatan sulphate. Children with Hurler's syndrome appear nearly normal
at birth but, left untreated, show a progressive mental and physical
deterioration caused by a build-up of GAGs in all organs of the body.
Death is often caused by cardiac or respiratory failure and usually
occurs before the second decade of life. In recent years, bone marrow
transplantation has been employed in the management of patients with
Hurler's syndrome.
Hunter syndrome,
mucopolysaccharidosis type II (MPS II), is a X-linked inherited disorder
caused by the deficiency of the enzyme iduronate-2-sulfatase (IDS),
involved in the lysosomal catabolism of the glycosaminoglycans (GAG)
dermatan and heparan sulfate. Such a deficiency leads to the
intracellular accumulation of undegraded GAG and eventually to a
progressive severe clinical pattern.
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In general, all forms are progressive
disorders characterized by one or more of the following:
Coarse facial features ;
Hepatosplenomegaly ; Corneal clouding ; Lesions of
cardiac valves ; Narrowing of coronary arteries ; Joint stiffness ;
Mental retardation. |
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Mucopolysaccharidoses.
Orthopade. 2008 Jan;37(1):24-30.
Mucopolysaccharidoses are a family of metabolic disorders
characterized by a deficiency in the catabolic lysosomal pathways.
They are rare, inherited diseases which lead to progressive
cellular, tissue and organ damage across a broad spectrum of
phenotypes. To prevent irreversible damage early diagnosis is
essential. Typical signs and symptoms are the thoracolumbar gibbus,
shortened and plumped metacarpal bones, hip dysplasia, deformed ribs
and ovoid vertebral bodies. Due to the typical deformation of the
pelvis hip dislocation occurs often in childhood. Bilateral carpal
tunnel syndrome is frequent. Bone marrow transplantation and enzyme
replacement therapy are available. Orthopaedic interventions are
based on individual therapeutic decisions and indications.
Cardiac structural
involvement in mucopolysaccharidoses.
Cardiology. 2002;98(1-2):18-20.
Mucopolysaccharidoses (MPS) are lysosomal storage disorders due to
impaired glycosaminoglycan degradation. Cardiac involvement is
present in most patients with MPS although its clinical impact is
still undetermined. Cardiovascular abnormalities were evaluated in
39 patients with MPS aged 4-22 years. Valvular lesions and different
forms of cardiac involvement were detected. The most common lesion
was thickening of the mitral valve with regurgitation or stenosis,
regardless of the MPS type. Mitral valve thickening was observed in
23 patients, aortic valve thickening in 11 patients and congestive
heart failure in only 1 patient with MPS III. The most severe
changes were registered for MPS types I and II. Complete
cardiological investigation should be routinely warranted in every
patient inflicted with MPS.
Ophthalmologic
signs in mucopolysaccharidoses: two case reports.
J Fr Ophtalmol. 2007 Feb;30(2):165-9.
BACKGROUND:
The mucopolysaccharidoses (MPS) form a group of heterogeneous
hereditary lysosomal storage diseases, distinguished by facial
dysmorphy in gargoyle-like facies. The enzymatic deficiency involves
the degradation of glycosaminoglycans, whose accumulation manifests
in severe general and ophthalmologic problems. CASES REPORT: We
report the cases of two 18-month-old girls consulting for corneal
clouding and photophobia. The diagnosis was made based on the facial
dysmorphy, then biologically corroborated: Scheie's syndrome (MPS
type I-S) and Hurler's syndrome (MPS type I-H). The corneal clouding
was isolated or associated with bilateral disc swelling. Enzyme
replacement therapy was instituted in both cases while waiting for
bone marrow transplantation, with a better prognosis in the first
case because of the type of MPS and the less severe neurological
involvement. DISCUSSION: The accumulation of glycosaminoglycans in
ocular tissues can involve stromal opacities, glaucoma, retinopathy,
and optic nerve swelling. Whereas the ophthalmological involvement
is often secondary, it can lead the ophthalmologist to the diagnosis
of MPS. The early diagnosis of MPS, before the onset of neurological
signs, is vital, since treatment can stop disease progression.
CONCLUSION: Better knowledge of the clinical signs of MPS on the
part of the ophthalmologists could improve the prognosis of these
patients.
Overview of enzyme
replacement therapy in mucopoly- saccharidosis.
Presse Med. 2007 Mar;36
Spec No 1:1S96-9.
Mucopolysaccharidosis are rare, multisystemic and progressive
diseases with an extremely various clinical spectrum. For the type
I, II and VI mucopolysaccharidosis, enzyme replacement therapy is
available. In these three diseases, enzyme replacement therapy
induces a reduction in urinary glycosaminoglycanes excretion and on
improvement in functional tests, 6 minutes walk test, pulmonary
function test and range of motion. |
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