7-dehydrocholesterol is used in the diagnosis of Smith-Lemli-Opitz syndrome. Blood and tissue of infants with Smith- Lemli-Opitz (SLO) syndrome contain reduced amounts of cholesterol and greatly increased concentrations of 7-dehydrocholesterol and of its isomer 8-dehydrocholesterol.
Features of this disease can include learning and behavioural problems. Physical abnormalities can be of varying severity; patients may have distinctive facial features, microcephaly, growth retardation, hypotonia, limb abnormalities, feeding difficulties and malformations of the heart, lungs, kidneys, gastrointestinal tract and genitalia.
For adults, blood taken into a 5mL gold top gel tube (or rust top for the Acute Unit) and protected from light
For children, blood taken into a 3.5mL rust top tube and protected from light
For neonates, blood taken into a 0.8ml minicollect tube and protected from light
- Do not store. Send at ambient temperature to the laboratory on same day as sample collection.
- 7-DHC is photosensitive, so blood samples must be protected from the light - wrap in foil or brown paper immediately after collection/labelling.
Relevant clinical details including details of clinical presentation.
Samples are sent for analysis to the North Bristol NHS Trust with a result expected within 6 weeks.
Plasma 7-dehydrocholesterol: less than 2.5 µmol/L
To learn more about 7-dehydrocholesterol visit National Metabolic Biochemistry Network or http://ghr.nlm.nih.gov/condition/smith-lemli-opitz-syndrome
Page last updated 20/04/2021