Sterols
Label Mnemonic: STERL
Epic Lab Code: LAB7475
Downtime Form: A-1a Miscellaneous Request
Commercial Mail-out Laboratory
5231 RCP
356-8593
Specimen(s):
Plasma
Collection Medium:
Green top tube 4 mL (Na Heparin)
Minimum:
1 mL plasma
Fasting (12 hours or more, infants just before next feeding).
Note: Patient's age and sex are required.
Rejection Criteria:
Specimens other than plasma.
Turn Around Time:
10 days
Reference Range:
DESMOSTEROL
0.0-2.0 mg/L

LATHOSTEROL
0.0-3.0 mg/L

CAMPESTEROL
0.0-7.0 mg/L

SITOSTEROL
0.0-5.0 mg/L

CHOLESTANOL
0.0-5.0 mg/L

Cautions:
Reference ranges were derived using fasting specimens from healthy individuals. Sitosterol and campesterol values may be mildly elevated in individuals whose diets include foods with high concentrations of plant sterols, such as some vegetable oils and infant formulas.
Interpretive Data:
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.
Comments:
Please print, complete and submit the Informed Consent for Genetic Testing to the lab, with the specimen and the A-1a Miscellaneous Request or Epic Req.

Testing includes desmosterol, lathosterol, campesterol, and sitosterol for the investigation of desmosterolosis and sitosterolemia.

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.
Methodology:
Gas Chromatography-Mass Spectrometry (GC-MS)/Gas Chromatography-Flame Ionization Detection (GC-FID)
CPT Code:
82542
 
See Additional Information:
Fasting Specimen Requirements