Cerebrotendinous xanthomatosis: reduced serum 26-hydroxycholesterol

Area of Science:

• Biochemistry
• Metabolic Disorders
• Clinical Chemistry

Background:

• Cerebrotendinous xanthomatosis (CTX) is a rare genetic disorder affecting lipid metabolism.
• Sterol and bile acid metabolism pathways involve complex enzymatic processes.
• Accurate quantification of specific sterols is crucial for diagnosing metabolic diseases.

Purpose of the Study:

• To quantify serum 26-hydroxycholesterol levels in normal individuals and CTX patients.
• To evaluate the utility of serum 26-hydroxycholesterol as a biomarker for CTX.
• To investigate the underlying enzymatic defect in CTX related to sterol metabolism.

Main Methods:

• Isotope dilution-mass spectrometry (IDMS) was employed for precise serum 26-hydroxycholesterol measurement.
• Serum samples were analyzed from a cohort of normal individuals.
• Serum samples were analyzed from patients diagnosed with cerebrotendinous xanthomatosis.

Main Results:

• Normal individuals exhibited serum 26-hydroxycholesterol concentrations ranging from 4.3 to 13.0 microgram/100 ml.
• CTX patients displayed significantly reduced levels, ranging from 0 to 0.6 microgram/100 ml.
• The observed low levels in CTX patients are consistent with impaired mitochondrial C27 steroid 26-hydroxylase activity.

Conclusions:

• Serum 26-hydroxycholesterol quantification is a valuable method for detecting cerebrotendinous xanthomatosis.
• This method may also be applicable to identifying other sterol and bile acid metabolism disturbances.
• Reduced C27 steroid 26-hydroxylase activity is the likely cause of altered 26-hydroxycholesterol levels in CTX.