The Relationship Between MTHFR C677T Gene Polymorphism, Hcy Level And Cognitive Function In Schizophrenia

Objectives: In this study,the cognitive function of the first untreated schizophrenic patients was studied.The serum homocysteine(Hcy)level and methylenetetrahydrofolate reductase(MTHFR)C677T gene were measured.To explore the relationship between cognitive function,Hcy level and MTHFR C677 T gene polymorphism in schizophrenics.To reveal the possible pathogenesis of cognitive impairment in schizophrenics and provide theoretical basis for early prevention and diagnosis.Methods: 100 first-episode untreated schizophrenia patients(patient group)and 100 healthy volunteers(control group)admitted to the Sixth People's Hospital of Hebei province from 2018.11—2019.11 were included.The PANSS scale was used to assess the psychiatric symptoms of the patients.Cognitive function was assessed by MCCB in the two groups.Hcy levels in the two groups were determined by cyclic enzymatic method.DNA was extracted from peripheral blood cells,and genotyping of MTHFR C677 T locus was performed by sequencing.Results:(1)Hcy level in the patients group was significantly higher than that in the control group,and the difference was statistically significant(P < 0.001).There were statistically significant differences in MTHFR C677 T genotype,allele frequency and TT gene homozygous distribution between the two groups(genotype = 6.254,P < 0.05;allele T > C,= 3.875,P < 0.05;TT gene homozygous = 6.006,P < 0.05).The scores of TMT A,HVLT,BVMT,CPT and Stroop in the MCCB test of cognitive function in the patient group were significantly lower than those in the control group(P < 0.05).(2)The Hcy level in the patient group was positively correlated with the negative symptom score in the PANSS scale(r=0.249,P=0.013),but not with the positive symptom score,general pathology score or total score.Hcy level was negatively correlated with TMT A(r=-0.333,P=0.001),HVLT(r=-0.315,P=0.001),BVMT(r=-0.372,P < 0.001),CPT(r=-0.344,P < 0.001)and Stroop color word test(r=-0.272,P=0.006).(3)In the comparison of cognitive function of different genotypes of MTHFR C677 T in the patient group,there were statistically significant differences in TMT A(F=4.929,P=0.009),HVLT(F=9.518,P < 0.001),BVMT(F=4.289,P=0.017),CPT(F=6.286,P=0.003),and Stroop color word test(F=6.011,P=0.004).Conclusions:(1)The Hcy level of schizophrenics is significantly higher than that of healthy people.There was significant difference in MTHFR C677 T polymorphism.(2)Patients with schizophrenia have extensive and significant impairment of cognitive function.(3)In schizophrenia,Hcy level was correlated with negative symptom score,cognitive function(information processing speed,attention and alertness,working memory,visual learning and word learning).(4)MTHFR C677 T gene polymorphism may be involved in the formation of cognitive dysfunction in schizophrenia.