The AUCs for AFP-L2 in the screening of trisomy 21, 18 fetuses were higher than those for AFP in trisomy 21, and lower than those for trisomy 18 (0.785 and 0.758 vs, 0.613; 0.775 and 0.754 vs, 0.869, respectively). The gene discussed is AFP; the disease is trisomy 18.