Aβ peptide, the cleavage product of APP believed to underlie the pathology of AD (Glenner and Wong, 1984; Masters et al., 1985; Gorevic et al., 1986; Selkoe et al., 1986), is not present in APL-1 (Daigle and Li, 1993) nor does C. elegans possess β-secretase activity to produce Aβ (Link, 2006). The gene discussed is ADI1; the disease is Alzheimer disease.