The remaining third includes four genes conserved in nematodes, fly, mouse, and human (zfp-1, R11F4.1, apl-1 and fcd-2) and whose human homologs are linked to disorders (AF10/MLLT10: leukemia, Glycerol kinase: hyperglycerolemia, APP: Alzheimer's, and FANCD2: Fanconi anemia). The gene discussed is APP; the disease is isolated glycerol kinase deficiency.