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

STER
82079
Useful For: As an aid in the diagnosis of steroid sulfatase deficiency syndrome, in conjunction with
CMS/8696 Chromosomes Analysis, for Congenital Disorders, Blood Detecting cryptic translocations
involving Xp22.3 that are not demonstrated by conventional chromosome studies
Interpretation: Any individual with a normal signal pattern (1 signal on the X homolog) in each
metaphase is considered negative for a deletion in the region tested by this probe. Any patient with a
FISH signal pattern indicating loss of the critical region will be reported as having a deletion of the
regions tested by this probe.
Reference Values:
An interpretive report will be provided.
Clinical References: 1. Ballabio A, Zollo M, Carrozzo R, et al: Deletion of the distal short arm of
the X chromosome (Xp) in a patient with short stature, chondrodysplasia punctata, and X-linked
ichthyosis due to steroid sulfatase deficiency. Am J Med Genet 1991;41:184-187 2. Foote S, Vollrath D,
Hilton A, Page DC: The human Y chromosome: overlapping DNA clones spanning the euchromatic
region. Science 1992;258:60-66 3. Schnur RE, Trask BJ, van den Engh G, et al: An Xp22 microdeletion
associated with ocular albinism and ichthyosis: approximation of breakpoints and estimation of deletion
size by using cloned DNA probes and flow cytometry. Am J Hum Genet 1989;45:706-720
Sterols, Plasma
Clinical Information: Cholesterol plays an essential role in many cellular and developmental
processes. In addition to its role as a membrane lipid, it is the precursor to numerous molecules that play
an important role in cell growth and differentiation, protein glycosylation, and signaling pathways. The
biosynthesis of cholesterol and its subsequent conversion to other essential compounds is complex,
involving a number of intermediates and enzymes. Disorders that result from a deficiency of these
enzymes lead to an accumulation of specific intermediates and inhibit the formation of important
biomolecules. Clinical findings common to cholesterol biosynthesis disorders include congenital
skeletal malformations, dysmorphic facial features, psychomotor retardation, and failure to thrive. One
example is desmosterolosis (desmosterol reductase deficiency), which has a similar phenotype to
Smith-Lemli-Opitz (SLO) syndrome (7-dehydrocholesterol reductase deficiency). Its biochemical
marker is the elevation of desmosterol in plasma, tissue, and cultured cells. Sitosterolemia is a rare
autosomal recessive disorder caused by mutations in 2 ATP-binding cassette (ABC) transporter genes,
ABCG5 and ABCG8, which abnormally enhance the absorption of plant sterols and cholesterol from
the intestines. Patients often present with tendon and tuberous xanthomas as well as premature coronary
artery disease. A biochemical diagnosis of sitosterolemia is made by documenting elevations of the
plant sterols sitosterol and campesterol in plasma or serum.
Useful For: Investigation of possible desmosterolosis (desmosterol reductase deficiency) and
sitosterolemia
Interpretation: Patients with sitosterolemia typically have campesterol values >40 mg/L and
sitosterol values >80 mg/L. A quantitative report of the patient's sterol profile and a Biochemical
Genetics consultant's interpretation is provided for each specimen.
Reference Values:
DESMOSTEROL
0.0-5.0 mg/L
LATHOSTEROL
0.0-7.0 mg/L
CAMPESTEROL
0.0-7.0 mg/L
SITOSTEROL
0.0-5.0 mg/L
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