Do FKBP5 rs1360780 and CRHR1 rs110402 variants increase HPA-axis rhythm dysregulation?

The hypothalamic-pituitary-adrenal (HPA) axis relies on a precise balance of hormone-driven forward signaling and negative feedback. Genetic variations in the regulatory genes FKBP5 and CRHR1 can disrupt these pathways, leading to systemic rhythm dysregulation and clinical vulnerability.

Mechanistic pathways of dysregulation

• Impaired GR Feedback (FKBP5 rs1360780): The rs1360780 T allele functions as a high-induction risk allele that facilitates chromatin looping to enhance FKBP5 co-chaperone transcription. Elevated FKBP5 binds to the cytosolic glucocorticoid receptor (GR)-Hsp90 complex, decreasing cortisol affinity and delaying GR nuclear translocation. This intracellular resistance weakens negative feedback, causing prolonged cortisol elevations after stress.
• Altered Anterior Signaling (CRHR1 rs110402): This intronic regulatory polymorphism influences the expression of the G-protein coupled CRH receptor 1 on pituitary corticotrophs. It alters the downstream adenylyl cyclase cascade and POMC transcription, modulating the peak and trajectory of ACTH release and initial stress reactivity.

Clinical and sleep implications

• HPA Rhythm Disruption: Combined alterations in forward signaling and delayed negative feedback directly disturb the diurnal cortisol slope and alter the cortisol awakening response.
• Sleep Disturbances: These genetic variations elevate the risk of stress-induced sleep disruption. The FKBP5 rs1360780 T allele (particularly the TT genotype) is linked to reduced sleep efficiency and increased wake time under stress, while the CRHR1 rs110402 G-allele is associated with an elevated risk of clinical sleep disturbances and insomnia.

Bottom line

• The CRHR1 rs110402 variant alters the initial threshold for HPA axis stress reactivity, while the FKBP5 rs1360780 variant impairs the subsequent receptor feedback shutdown, synergistically increasing vulnerability to chronic HPA-axis rhythm dysregulation and sleep disturbances.