 Sitosterolemia is inherited as a rare autosomal recessive condition.It has been shown to result from mutations in either of two adjacent and oppositely oriented genes (ABCG5 and ABCG8) located in chromosome 2 in band 2p21 and encode for ABC transporter proteins named sterolin-1 and sterolin-2, respectively.Thus, the active pumping back into the intestine of passively absorbed plant sterols is disrupted, and hepatic secretion of the resultant accumulation of these sterols is decreased.