SMITH-LEMLI-OPITZ SCREEN, PLASMA

Code
000.0000
Name
SMITH-LEMLI-OPITZ SCREEN, PLASMA
Category
None
Department
Send-Out
Start Date
Expiration Date
Synonyms
7-dehydrocholesterol; 8-dehydrocholesterol; RSH syndrome
CPT Codes
82541
Site
SBMF
Reference Test
42157
ATLAS Test Code

Specimen Information

Type

Green, Heparin

Volume

1.0 ml

Transport Info

Centrifuge and immediately transfer plasma to separate plastic tube
Frozen

Fasting Required?
False
Patient Instructions

Patient should be fasting (12 hours or more, infants just before next feeding)

Reference Range

Negative (reported as positive or negative)
Quantitative results are provided when positive

Methodology

Gas Chromatography/Mass Spectrometry (GC/MS)

Clinical Significance

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. In addition to an accumulation of specific intermediates, defects in this pathway may result in a deficiency of cholesterol. Clinical findings common to cholesterol biosynthesis disorders include congenital skeletal malformations, dysmorphic facial features, psychomotor retardation, and failure to thrive.

Smith-Lemli-Opitz syndrome (7-dehydrocholesterol reductase deficiency) is an autosomal recessive disorder characterized by markedly increased plasma concentrations of 7-dehydrocholesterol (7-DHC) and 8-DHC levels. Severity ranges from mild to severe. Clinical features include microcephaly, growth retardation, developmental delay, dysmorphic facial features, limb abnormalities (especially syndactyly and polydactyly of the toes), and heart and kidney malfunctions. The estimated incidence is between 1:10,000 and 1:60,000.

Other disorders of cholesterol biosynthesis, including desmosterolosis (desmosterol reductase deficiency) and sitosterolemia, may present with similar manifestations. These disorders can be detected biochemically by performing a quantitative profile of plasma sterols.

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