Sorted By Test Name - Mayo Medical Laboratories

9831
MCIV
85321
MPSSC
84464
Mucicarmine Stain for Mucin
Reference Values:
The laboratory will provide a pathology consultation and stained slide.
Mucolipidosis IV, Mutation Analysis, IVS3(-2)A->G and del6.4kb
Clinical Information: Mucolipidosis IV is a lysosomal storage disease characterized by mental
retardation, hypotonia, corneal clouding, and retinal degeneration. Mutations in the MCOLN1 gene are
responsible for the clinical manifestations of mucolipidosis IV. The carrier rate in the Ashkenazi Jewish
population is 1/127. Two mutations in the MCOLN1 gene account for the majority of mutations in the
Ashkenazi Jewish population: IVS3(-2)A->G and del6.4kb. The detection rate for these 2 mutations is
approximately 95%.
Useful For: Carrier testing for individuals of Ashkenazi Jewish ancestry Prenatal diagnosis for at-risk
pregnancies Confirmation of suspected clinical diagnosis of mucolipidosis IV in individuals of Ashkenazi
Jewish ancestry
Interpretation: An interpretive report will be provided.
Reference Values:
An interpretive report will be provided.
Clinical References: 1. Gross SJ, Pletcher BA, Monaghan KG: Carrier screening in individuals of
Ashkenazi Jewish descent. Genet Med. 2008 Jan;10(1):54-56 2. Bach G: Mucolipidosis type IV. Mol
Genet Metab 2001;73(3):197-203
Mucopolysaccharides (MPS) Screen, Urine
Clinical Information: The mucopolysaccharidoses (MPSs) 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 excreted in the urine.
Accumulation of GAGs in lysosomes interferes with normal functioning of cells, tissues, and organs
resulting in the clinical features observed in MPS disorders. There are 11 known enzyme deficiencies that
result in MPSs. In addition, abnormal GAG storage is observed in multiple sulfatase deficiency and in
I-cell disease. Finally, an abnormal excretion of GAGs in urine is observed occasionally in other disorders
including active bone diseases, connective tissue disease, hypothyroidism, urinary dysfunction, and
oligosaccharidoses. MPSs are autosomal recessive disorders with the exception of MPS II, which follows
an X-linked inheritance pattern. Affected individuals typically experience a period of normal growth and
development followed by progressive disease involvement encompassing multiple systems. The severity
and features vary, and may include facial coarsening, organomegaly, skeletal changes, cardiac
abnormalities, and developmental delays. Moreover, disease presentation varies from as early as late
infancy to adulthood. Additional information regarding these disorders is below. A diagnostic workup for
individuals with suspected MPS begins with Mayo Medical Laboratories' test MPSSC/84464
Mucopolysaccharides (MPS) Screen, Urine, which includes both the quantitative analysis of total GAGs
and thin layer chromatography (TLC). Interpretation is based upon pattern recognition of the specific
sulfate(s) detected on TLC and the qualitative analysis of their relative amounts of excretion (see Table).
However, an abnormal MPS analysis is not sufficient to conclusively establish a specific diagnosis. It is
strongly recommended to seek confirmation by an independent method, typically in vitro enzyme assay
(available in either blood or cultured fibroblasts from a skin biopsy) and/or molecular analysis. After a
specific diagnosis has been established, Mayo Medical Laboratories' test MPSQN/81473
Mucopolysaccharides (MPS), Quantitative, Urine, which does not include the TLC, can be appropriate for
monitoring the effectiveness of a bone marrow transplant or enzyme replacement therapy. However, some
clinicians will opt to perform the MPS screen, which allows for monitoring of not only the total amount of
GAGs, but also the excretion of specific sulfates, as these may change in patients with an MPS disorder
undergoing treatment. Table: Enzyme Defects and Excretion Products of Mucopolysaccaridoses Disorder
Current as of January 4, 2013 7:15 pm CST 800-533-1710 or 507-266-5700 or MayoMedicalLaboratories.com Page 1244