We aimed to investigate the quantitative detection of methylated suppressor of cytokine signaling-1 (SOCS-1) in schizophrenia (SCZ) and bipolar disorder (BD), considering SOCS-1 -1478CA/del polymorphism and clinical parameters.
Our research is a case-control study in which 114 patients with SCZ, 86 patients with BD, and 80 volunteers as a healthy group participated. Bisulfite-converted DNA samples were analyzed using the real-time quantitative methylation-specific PCR (qMS-PCR) method to measure the methylation level of the SOCS-1 gene. In addition, SOCS-1 -1478CA/del gene polymorphism was analyzed with the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).
When the SOCS-1 promoter methylation levels of SCZ and BD patients were compared with the control group, the methylation levels of SCZ and BD were significantly lower than the control group. An earlier age of illness onset was significantly related to the SOCS-1 promoter hypermethylation in DNA samples of SCZ patients. Again, SOCS-1 promoter hypermethylation was significantly associated with the higher Young Mania Rating Scale (YMRS) score in BD patients. While the SOCS-1 CA/CA genotype frequency was significantly higher in the control group than in the BD group, the del/del genotype was significantly related to a higher frequency of rapid cycling and a lower frequency of family history in the BD patient group.
In summary, the methylated SOCS-1 quantity in DNA samples of SCZ and BD patients were significantly lower than in control samples. Whereas the SOCS-1 -1478CA/del polymorphism was not related to SCZ, it may be associated with the BD.

© 2022. The Author(s), under exclusive licence to Royal Academy of Medicine in Ireland.