Development of a Genetic Test Indicating Increased AVP/V1b Signalling in Patients with Acute Depression.

Area of Science:

• Neurobiology
• Genetics
• Endocrinology

Background:

• A subset of patients with acute depression exhibit dysregulation of the hypothalamic-pituitary-adrenocortical (HPA) axis.
• This HPA axis dysfunction is often linked to overactive arginine-vasopressin (AVP)/V1b receptor signaling.
• The combined dexamethasone/corticotropin-releasing hormone (dex/CRH) test can diagnose this, but its procedure is complex.

Purpose of the Study:

• To develop a genetic variant-based method to predict the outcome of the dex/CRH-test in patients with acute depression.
• To establish a simpler, more accessible diagnostic tool for HPA axis dysregulation in depression.

Main Methods:

• Genome-wide interaction analysis was conducted on 352 severe depression patients who underwent the dex/CRH-test.
• The analysis focused on single nucleotide polymorphisms (SNPs) upstream of the V1b-receptor gene to predict adrenocorticotropic hormone (ACTH) response.
• A probabilistic neural network algorithm was employed to build the predictive model.

Main Results:

• The developed gene test achieved 93.5% overall accuracy in identifying high ACTH responders in the dex/CRH-test (90% sensitivity, 95% specificity).
• Pituitary RNA sequencing confirmed that identified genetic interactions correspond to a functional transcript network in the pituitary gland.
• The strength of these transcript interactions was significantly greater than expected by chance.

Conclusions:

• The gene test serves as a reliable proxy for hyperactive AVP/V1b signaling in acute depression.
• This genetic approach has potential as a companion diagnostic for identifying patients suitable for drugs targeting the AVP/V1b signaling pathway.
• It offers a promising alternative to the complex dex/CRH test for clinical application.