Regarding the beneficial effect of phytosterol supplementation on cholesterolemia, apotential negative effect is phytosterolemia, also known as sitosterolemia, a rareinherited autosomal recessive disorder which is related to mutation in the genes ofthe cotransporters of phytosterols/cholesterol, ABCG5 and ABCG8. This evidence concerns the gene ABCG8 and sitosterolemia.