7-Dehydrocholesterol (7-DHC)

Biochemistry Blood Sciences Test

Specimen Type

Lithium Heparin Plasma (preferred) or serum

Special pre-analytical handling requirements:

None

Reference ranges and test units

Age and sex appropriate reference ranges and units are reported with all clinical results.

Test Use

Smith–Lemli–Opitz syndrome (also SLOS, or 7-dehydrocholesterol reductase deficiency) is an autosomal recessive metabolic and developmental congenital disorder that causes the inability to correctly produce or synthesize cholesterol due to a low concentration of 7-DHC reductase, an enzyme involved in cholesterol synthesis.

Cases of SLOS can vary widely in their clinical presentation. It is characterized by multiple congenital anomalies, but not all features are present in all affected individuals. The most commonly observed features include:

Characteristic dysmorphic faces
Microcephaly
Syndactyly (most commonly of the second and third toes)
Polydactyly
Growth retardation
Intellectual disability
Cleft palate
Hypospadias (males only)

Performing laboratory

This test is referred to an external laboratory for analysis. Follow-up, confirmatory testing is required in low enzyme activity. These requests are triaged by the Genomics Department.

Turnaround Time and add-on availability

2 – 4 weeks

This test cannot be added on to an existing sample.

UKAS accreditation

Please refer to the UKAS website for test accreditation status.

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Specimen Labelling Procedure