Peripheral clock system circadian abnormalities in Cushing’s disease

In Cushing's disease patients (n = 12), the circadian variation in clock gene expression is lost.

• Cushing's syndrome is associated with impaired cortisol rhythms and disrupted clock gene expression.
• Healthy individuals (n = 13) exhibited circadian variations in the expression of certain clock genes.
• In healthy leukocytes, specific clock genes showed a late afternoon peak in expression, while others peaked at night.
• Cushing's disease patients maintained some circadian variation in clock gene expression but lost the overall rhythmic pattern.
• Higher expression of certain clock genes at night in patients may play a role in disrupted cortisol regulation.

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