Sorted By Test Name - Mayo Medical Laboratories

ARSB
8151
ASCRI
82764
Roth. McGraw-Hill Companies, 2009, pp 742-743 2. von Figura K, Gieselmann V, Jacken J:
Metachromatic leukodystrophy. In The Metabolic and Molecular Basis of Inherited Disease. Vol. 3. 8th
edition. Edited by CR Scriver, AL Beaudet, WS Sly, D Valle. New York, McGraw-Hill Book Company,
2001, pp 3695-3716
Arylsulfatase B, Fibroblasts
Clinical Information: Mucopolysaccharidosis VI (MPS VI, Maroteaux-Lamy syndrome) is an
autosomal recessive lysosomal storage disorder caused by the deficiency of N-acetylgalactosamine
4-sulfatase (arylsulfatase B [ARSB]). The mucopolysaccharidoses are a group of disorders caused by the
deficiency of any of the enzymes involved in the stepwise degradation of dermatan sulfate, heparan
sulfate, keratan sulfate, or chondroitin sulfate (glycosaminoglycans, [GAGs]). Undegraded or partially
degraded GAGs (also called mucopolysaccharides) are stored in lysosomes and/or are excreted in urine.
Accumulation of GAGs (previously called mucopolysaccharides) in lysosomes interferes with normal
functioning of cells, tissues, and organs. MPS VI is caused by a reduced or absent activity of the ARSB
enzyme and gives rise to the physical manifestations of the disease. Clinical features and severity of
symptoms are widely variable, but typically include short stature, dysostosis multiplex, facial
dysmorphism, stiff joints, hepatosplenomegaly, corneal clouding, and/or cardiac defects. Intelligence is
usually normal. Estimates of the incidence of MPS VI range from 1 in 250,000 to 1 in 300,000. Treatment
options include hematopoietic stem cell transplantation and/or enzyme replacement therapy. A diagnostic
workup in an individual with MPS VI typically demonstrates elevated levels of urinary GAGs and
increased dermatan sulfate detected on thin-layer chromatography. Reduced or absent activity of ARSB in
leukocytes and/or fibroblasts indicates a diagnosis of MPS VI. Sequencing of the ARSB gene allows for
detection of disease-causing mutations in affected patients and identification of familial mutations allows
for testing of at-risk family members. Currently, no clear genotype-phenotype correlations have been
established.
Useful For: Diagnosis of mucopolysaccharidosis VI (Maroteaux-Lamy syndrome)
Interpretation: Deficiency of arylsulfatase B is diagnostic of mucopolysaccharidosis VI.
Reference Values:
1.6-14.9 U/g of cellular protein
Clinical References: 1. Valayannopoulos V, Nicely H, Harmatz P, Turbeville S:
Mucopolysaccharidosis VI. Orphanet J Rare Dis. 2010 Apr 12;5:5 2. Neufeld EF, Muenzer J: The
Mucopolysaccharidoses: In The Metabolic Basis of Inherited Disease. 7th edition. Edited by CR Scriver,
AL Beaudet, WS Sly, D Valle. New York, McGraw-Hill 1995, pp 2465-2494 3. Enns GM, Steiner RD,
Cowan TM: Lysosomal Disorders. In Pediatric Endocrinology and Inborn Errors of Metabolism. Edited
by K Sarafoglou, GF Hoffmann, KS Roth, New York, McGraw-Hill Medical Division, 2009, pp 733-735
Ascaris, IgE
Clinical Information: Clinical manifestations of immediate hypersensitivity (allergic) diseases are
caused by the release of proinflammatory mediators (histamine, leukotrienes, and prostaglandins) from
immunoglobulin E (IgE)-sensitized effector cells (mast cells and basophils) when cell-bound IgE
antibodies interact with allergen. In vitro serum testing for IgE antibodies provides an indication of the
immune response to allergen(s) that may be associated with allergic disease. The allergens chosen for
testing often depend upon the age of the patient, history of allergen exposure, season of the year, and
clinical manifestations. In individuals predisposed to develop allergic disease(s), the sequence of
sensitization and clinical manifestations proceed as follows: eczema and respiratory disease (rhinitis and
bronchospasm) in infants and children less than 5 years due to food sensitivity (milk, egg, soy, and wheat
proteins) followed by respiratory disease (rhinitis and asthma) in older children and adults due to
sensitivity to inhalant allergens (dust mite, mold, and pollen inhalants).
Useful For: Testing for IgE antibodies may be useful to establish the diagnosis of an allergic disease
and to define the allergens responsible for eliciting signs and symptoms. Testing also may be useful to
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