Second, a recent study (20) has shown that an increased presence of the cleavage products of all of these theoretical cuts is measurable in the CSF of individuals who have a genetically constitutionally increased dose of BACE2, those with Down syndrome (DS), as this syndrome is caused by aneuploidy, with an extra chromosome 21 that harbors BACE2. This evidence concerns the gene BACE2 and Dravet syndrome.