Cholestanol in plasma (investigation of CTX)
Clinical Background:
Cholestanol, an intermediate in the synthesis of bile acids from cholesterol, is measured in plasma in the investigation of the rare inherited metabolic disorder cerebrotendinous xanthomatosis (CTX...
Cholestanol, an intermediate in the synthesis of bile acids from cholesterol, is measured in plasma in the investigation of the rare inherited metabolic disorder cerebrotendinous xanthomatosis (CTX, sterol 27-hydroxylase deficiency).
Patients with CTX usually have adult-onset progressive neurological dysfunction, tendon xanthomas, premature atherosclerosis, osteoporosis and respiratory insufficiency with normal cholesterol. Some patients present early in life with cholestatic jaundice which resolves, mental retardation and cataracts. Clinical features of the disorder are very variable and the diagnosis is often delayed.
Test Details
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Discipline:
Biochemistry
Biochemistry
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Specimen Container Adult:
Lithium heparin plasma
Lithium heparin plasma
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Specimen Container Paediatric:
Lithium heparin plasma
Lithium heparin plasma
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Minimum Volume Adult:
2 mL blood, 1 mL plasma
2 mL blood, 1 mL plasma
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Minimum Volume Paediatric:
1 mL blood, 0.5 mL plasma
1 mL blood, 0.5 mL plasma
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Special Requirement:
Blood sample should be centrifuged on receipt in the laboratory and the plasma separated and frozen.
Blood sample should be centrifuged on receipt in the laboratory and the plasma separated and frozen.
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Transport Requirements:
NUTH users: send sample to the laboratory at ambient temperature
External hospitals: send sample to the RVI frozen and protected from light
NUTH users: send sample to the laboratory at ambient temperature
External hospitals: send sample to the RVI frozen and protected from light
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Interpretation:
Patients with CTX have very high circulating levels of cholestanol.
Mildly increased cholestanol is also found in patients with familial hypercholesterolaemia so use of the sterol/cholesterol ra...
Read MorePatients with CTX have very high circulating levels of cholestanol.
Mildly increased cholestanol is also found in patients with familial hypercholesterolaemia so use of the sterol/cholesterol ratio can improve the diagnostic sensitivity and specificity of the test.
Exposure to light may cause degradation of sterols.
A diagnosis of CTX should be confirmed by gene mutation analysis.
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Reference Ranges:
Cholestanol < 12.5 µmol/L (18 yrs or over), < 15.7 µmol/L (< 18 yrs)
Cholestanol/cholesterol 1.00 – 2.70 µmol/mmol (18 yrs or over), 1.14 – 3.34 µmol/m...
Read MoreCholestanol < 12.5 µmol/L (18 yrs or over), < 15.7 µmol/L (< 18 yrs)
Cholestanol/cholesterol 1.00 – 2.70 µmol/mmol (18 yrs or over), 1.14 – 3.34 µmol/mmol (< 18 yrs)
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Other Info:
Serum or EDTA plasma are also acceptable, but must be protected from light.
Serum or EDTA plasma are also acceptable, but must be protected from light.
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Routine Contact Name:
Duty Biochemist
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Routine Telephone:
Freeman: 0191 244 8889
RVI: 0191 282 9719
Freeman: 0191 244 8889
RVI: 0191 282 9719
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Routine Email:
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Specialist Test:
Yes
Yes
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Specialist Contact Name:
Metabolic Clinical Scientist
Metabolic Clinical Scientist
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Specialist Telephone:
0191 282 9685 (Consultant Clinical Scientist)
0191 282 0334 (Metabolic Laboratory)
0191 282 9685 (Consultant Clinical Scientist)
0191 282 0334 (Metabolic Laboratory)
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Specialist Email: