Firstly, we see a recessive association between a missense variant (chr1:11796321G>A, rs1801133; c.677C>T [p.Ala222Val]) in the gene encoding methylenetetrahydrofolate reductase (MTHFR) and folate deficiency (OR = 2.1, p = 5 × 10−9, dominance deviation p = 10−3). The gene discussed is MTHFR; the disease is folate deficiency.