The first, carrying a missense R174Q mutation, which acts as a dominant-negative mutant, is associated with thrombocytopenia and leukemia, and the second, carrying a monoallelic gene deletion inducing a haploinsufficiency, presents only as thrombocytopenia.
The NQO1 rs1800566 (C609T), PON1 rs854560 (L55M), and PON1 rs662 (Q192R) polymorphisms modified risk depending on leukemia subtype (decreased in AML, increased and decreased in ALL, respectively), age strata, and variant genotype combinations.