No significant interaction was identified. (All interaction P >.05)The detrimental effect of high total fat intake and high trans-fat intake was more prominent in wild type carriers of the CASP9 + 93C/T polymorphism than in the individuals with CASP9 + 93C/T mutation.The deleterious effect of n-6 PUFA on CD disease activity was only significantly observed among the individuals homozygous for wild type of FASLG-843C/T. The gene discussed is CASP9; the disease is Cowden disease.