The dramatic increase in the expression of APP and S100B in DS suggests that (i) some gene product on chromosome 21 is dramatically inducing the APP and S100B synthesis in DS and or (ii) some chromosome 21 gene is indirectly inducing such excessive synthesis, via induction of a gene product on another chromosome, which, in turn, induces excessive expression of APP and S100B. The gene discussed is APP; the disease is Dravet syndrome.