Risk factors for the development of pancytopenia include: advanced age, renal failure, hypoalbuminaemia, daily intake of MTX due to medication error, absence of folic acid substitution, polypharmacy [288], and being a carrier of the C677T polymorphism of methylenetetrahydrofolate reductase (MTHFR) [289]. The gene discussed is MTHFR; the disease is acute kidney injury.