7-Dehydrocholesterol

Specimen

Lithium Hep Plasma

Units

umol/L

Test Usage

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 occurrence 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)

A diagnosis of SLOS is often made after a clinician observes a patient with a clustering of these features, and orders a blood test to measure the concentraton of 7-dehydrocholesterol in the blood. Further confirmation of diagnosis can be done by molecular genetic analysis of the DHCR7 gene

Availability

Referred test