Under these conditions the use of the lipid profile of proband’s parents is essential to lead and facilitate the molecular diagnosis of these metabolic disorders: familial hypobetalipoproteinemia is a rare autosomal codominant disorder of lipoprotein metabolism, it results that both parents are expected to have plasma levels of TC, LDL-C and apoB lower than those found in normal subjects [3,19]. This evidence concerns the gene APOB and hypobetalipoproteinemia.