MTHFR C677T rs1801133 and TP53 Pro72Arg rs1042522 gene variants in South African Indian and Caucasian psoriatic arthritis patients

Methylenetetrahydrofolate reductase (MTHFR) gene is involved in homocysteine and folic acid metabolism. Tumour suppressor protein TP53 gene maintains cellular and genetic integrity. To date, no studies associated the MTHFR C677T rs1801133 and TP53 Pro72Arg rs1042522 with CRP levels and methotrexate (a folic acid antagonist) treatment outcomes in psoriatic arthritis (PsA) patients. The present study aimed to investigate whether the MTHFR rs1801133 and TP53 rs1042522 gene variants influences CRP levels and methotrexate treatment outcomes in South African Indian and Caucasian PsA patients. PsA patients (n=114) and healthy controls (n=100) were genotyped for the rs1801133 and rs1042522 using RFLP-PCR. (i) Results for rs1801133 genotyping: Caucasian patients had a higher frequency of the variant T-allele versus healthy Caucasian controls (40% versus 22%; OR=2.31, 95% CI=1.10-4.88, p=0.0379). Patients with the variant CT+TT genotypes had higher median CRP levels at baseline versus wildtype CC genotypes (11.70 (5.3-28.80) mg/mL versus 7.40 (5.00-15.05) mg/mL, p=0.0355). After 6 months of methotrexate treatment median CRP levels between genotypes reduced and remained similar. (ii) Results for rs1042522 genotyping: Indian patients had a higher frequency of the variant Arg-allele versus healthy Indian controls (42% versus 29%; OR=1.75, 95% CI=1.07-2.86, p=0.0275). In conclusion, patients with the MTHFR rs1801133 variant T-allele have elevated CRP levels, which can be ameliorated with methotrexate.