Does CRHR1 rs110402 AG create intermediate ACTH-cortisol stress reactivity?

The corticotropin-releasing hormone receptor 1 (CRHR1) gene is a central regulator of the hypothalamic-pituitary-adrenal (HPA) axis, coordinating the endocrine response to environmental stressors. The single nucleotide polymorphism (SNP) rs110402 plays a critical role in modulating how upstream stress signals are translated into systemic cortisol and adrenocorticotropic hormone (ACTH) release.

Endocrine reactivity and stress sensitivity

• Intermediate physiological output: Under additive genetic models of stress reactivity, individuals carrying the heterozygous AG genotype for CRHR1 rs110402 exhibit intermediate physiological phenotypes. During acute challenges like the Trier Social Stress Test (TSST), AG individuals display moderate baseline and peak cortisol responses positioned between those of AA and GG homozygotes.
• Environmental modulation: The effect of the AG genotype is highly context-dependent and heavily influenced by early-life adversity. For instance, while GG homozygotes show pronounced HPA-axis hyper-reactivity following childhood maltreatment, AG heterozygotes exhibit a more blunted, intermediate endocrine response to stress.

Neurological mechanisms

• Cortical and limbic processing: Functional neuroimaging during psychosocial stress shows that the rs110402 polymorphism modulates neural processing, specifically altering activation within the dorsal anterior cingulate cortex (dACC) and corticolimbic networks.
• Translational pathway: This altered dACC and corticolimbic activity directly correlates with downstream cortisol secretion, illustrating how genetic variations in CRHR1 translate neural stress perception into endocrine output.

Bottom line

• The CRHR1 rs110402 AG genotype acts as a biological modifier that establishes intermediate endocrine reactivity and dACC neural sensitivity, representing a moderate physiological phenotype that is highly shaped by environmental history and childhood stress.