Abetalipoproteinemia (ABL) and homozygous hypobetalipoproteinemia (HHBL) are syndromes resulting from the total absence or extremely low levels of apolipoprotein B. These patients present similarly during infancy with fatty diarrhea and associated fat-soluble vitamin malabsorption (Leppert et al. 1988; Zamel et al. 2008). The gene discussed is APOB; the disease is abetalipoproteinemia.