Associations between depression severity and purinergic receptor P2RX7 gene polymorphisms

Area of Science:

• Genetics
• Psychiatry
• Molecular Biology

Background:

• Major depressive disorder (MDD) and bipolar disorder (BPD) exhibit significant genetic influences.
• The P2RX7 gene, encoding the P2X7 purinergic receptor, is implicated as a potential susceptibility gene for both MDD and BPD.

Purpose of the Study:

• To investigate the genetic effects of specific P2RX7 gene variants, rs2230912 (Gln460Arg) and rs1653625, on mood disorders.
• To explore the association between these genetic variations and the severity of depressive symptoms in patients with MDD and BPD.

Main Methods:

• Genotype frequencies were determined in 315 patients (195 MDD, 120 BPD) and 373 controls.
• Depression severity was assessed using the Montgomery-Åsberg Depression Rating Scale (MADRS) and the Hospital Anxiety and Depression Scale (HADS).

Main Results:

• No significant differences in genotype frequencies were found between BPD/MDD cases and controls.
• BPD patients with the rs2230912 G-allele showed higher MADRS and HADS-depression scores (p=0.028, p=0.003).
• The rs1653625 AA genotype was also linked to higher depression scores in BPD patients (p=0.019 for MADRS, p=0.017 for HADS). The rs2230912 association with HADS remained significant after multiple testing correction (p<0.006), explaining 9% of the variance.

Conclusions:

• The study supports an association between the P2RX7 gene and the severity of depressive symptoms specifically in bipolar disorder patients.
• Further replication studies are recommended due to the relatively small sample size of BPD patients.