Mayo Test Catalog, (Sorted By Test Name) - Mayo Medical ...

CTSA
81979
4 17.5-49.9 Strongly positive
5 50.0-99.9 Strongly positive
6 > or =100 Strongly positive Reference values
apply to all ages.
Clinical References: Homburger HA: Allergic diseases. In Clinical Diagnosis and Management by
Laboratory Methods. 21st edition. Edited by RA McPherson, MR Pincus. New York, WB Saunders
Company, 2007, Chapter 53, Part VI, pp 961-971
Ceramide Trihexoside/Sulfatide Accumulation in Urine
Sediment, Urine
Clinical Information: Fabry disease is an X-linked recessive lysosomal storage disorder caused by
a deficiency of the enzyme alpha-galactosidase A (alpha-Gal A). Reduced enzyme activity results in
accumulation of glycosphingolipids in the lysosomes throughout the body, in particular, the kidney,
heart, and brain. Severity and onset of symptoms are dependent on the residual enzyme activity. Males
with 1% activity may present with
either of 2 variant forms of Fabry disease (renal or cardiac) with onset of symptoms later in life.
Individuals with the renal variant typically present in the third decade of life with the development of
renal insufficiency and, ultimately, end-stage renal disease. Individuals with the renal variant may or
may not share other symptoms with the classic form of Fabry disease. Individuals with the cardiac
variant are often asymptomatic until they present with cardiac findings such as cardiomyopathy, mitral
insufficiency, or conduction abnormalities in the fourth decade. The cardiac variant is not associated
with renal failure. Variant forms of Fabry disease may be underdiagnosed. Females who are carriers of
Fabry disease can have clinical presentations ranging from asymptomatic to severely affected, and may
have alpha-Gal A activity in the normal range. Individuals with Fabry disease, regardless of the severity
of symptoms, may show an increased excretion of ceramide trihexoside in urine. Metachromatic
leukodystrophy (MLD) is an autosomal recessive lysosomal storage disorder caused by a deficiency of
the arylsulfatase A enzyme, which leads to the accumulation of various sulfatides in the brain, nervous
system, and visceral organs, including the kidney and gallbladder. The 3 clinical forms of MLD are
late-infantile, juvenile, and adult, depending on age of onset. All result in progressive neurologic
changes and leukodystrophy demonstrated on magnetic resonance imaging. Late-infantile MLD is the
most common (50%-60% of cases) and typically presents between 1 and 2 years of age with hypotonia,
clumsiness, diminished reflexes, and slurred speech. Progressive neurodegeneration occurs with a
typical disease course of 3 to 10 years. Juvenile MLD (20%-30% of cases) is characterized by onset
between 4 and 14 years. Typical presenting features are behavior problems, declining school
performance, clumsiness, and slurred speech. Neurodegeneration occurs at a somewhat slower and more
variable rate than the late-infantile form. Adult MLD (15%-20% of cases) has an onset after puberty and
can be as late as the fourth or fifth decade. Presenting features are often behavior and personality
changes, including psychiatric symptoms; clumsiness, neurologic symptoms, and seizures are also
common. The disease course has variable progression and may occur over 2 to 3 decades. Individuals
with MLD typically show an increased excretion of sulfatides in urine. Extremely low arylsulfatase A
levels have been found in some clinically normal parents and other relatives of MLD patients. These
individuals do not have metachromatic deposits in peripheral nerve tissues, and their urine content of
sulfatide is normal. Individuals with this "pseudodeficiency" have been recognized with increasing
frequency among patients with other apparently unrelated neurologic conditions as well as among the
general population. This has been associated with a fairly common polymorphism in the arylsulfatase A
gene, which leads to low expression of the enzyme (5%-20% of normal). These patients can be difficult
to differentiate from actual MLD patients.
Useful For: As an aid in identifying patients with Fabry disease As an aid in identifying patients with
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