Severe Adverse Toxic Effects of Low-Dose Methotrexate Treatment on an Ectopic Pregnancy Patient With Methylenetetrahydrofolate Reductase Mutations: A Case Report

Background: Low-dose methylenetetrahydrofolate (LD-MTX) has been widely used for the treatment of the ectopic pregnancy (EP) for many decades, and related severe adverse toxic effects are rare. Current studies have shown that the polymorphisms of methylenetetrahydrofolate reductase (MTHFR) gene can decrease the MTX clearance, leading to the metabolite accumulation. However, there is a lack of literature report on an MTHFR gene polymorphism associated with adverse toxic effects resulting from the use of LD-MTX in an EP. Case Presentation: We report a rare case of a 38-year-old female who developed persistent fever, grade IV myelosuppression, skin lesions, mucositis, and liver injury after single dose of LDMTX to treat EP. The personalized genetic testing showed that MTHFR TT (677C>T) and MTHFR AA (1298A>C) were detected. Gradually, the symptoms improved after calcium leucovorin (CF) rescue, continuous renal replacement therapy (CRRT), promoting blood system regeneration, and multiple supportive treatments. Conclusion: This is the first report on the serious adverse toxic effects of LD-MTX on an EP patient with MTHFR mutations. We aim to alert obstetricians and gynecologists to this rare condition. The unexpected life-threatening toxicity with LD-MTX should be highly considered and recognized early. In particular, some easily overlooked gastrointestinal, skin, and mucosal symptoms occur earlier than severe myelosuppression. When toxic effects are suspected, detecting the polymorphisms of an MTHFR gene and monitoring MTX concentration in blood could assist us to formulate individualized and active treatments.

Influence of MTHFR C677T Polymorphism on High-Dose Methotrexate-Related Toxicity in Patients With Primary Central Nervous System Diffuse Large B-Cell Lymphoma

BACKGROUND

Primary central nervous system diffuse large B-cell lymphoma (PCNS-DLBCL) is a relatively rare and aggressive neoplasm. High-dose methotrexate (HD-MTX) is an effective regimen for the treatment of PCNS-DLBCL, but MTX-related toxicity remains a problem. The aim of this analysis study was to investigate the influence of the methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism on HD-MTX-related toxicity in patients with PCNS-DLBCL.

MATERIAL/METHODS

A prospective, observational study was conducted to analyze 148 MTX courses in 32 patients with PCNS-DLBCL.

RESULTS

The delayed MTX clearance was observed in 53 cycles (35.8%). The patients carrying the homozygous variant genotype had a higher risk of developing nephrotoxicity than those carrying the wild-type genotype (odds ratio [OR] 13.08; 95% confidence interval [CI], 1.65-103.86; P = .002) or heterozygous variant genotype (OR 8.43; 95% CI, 2.31-30.70; P < .001). Significant differences were observed in hepatotoxicity (OR 9.33; 95% CI, 2.54-34.27; P < .001) and hematologic toxicity (OR 3.09; 95% CI, 1.18-8.07; P = .024) in addition to nephrotoxicity between the homozygous variant genotype and the wild-type genotype.

CONCLUSION

The homozygous mutation of C to T at nucleotide 677 increases the risk on HD-MTX-related toxicity. The MTHFR C677T polymorphism can be used to predict HD-MTX-related toxicity for patients with PCNS-DLBCL.