For our case study, we used the Ts65Dn (TS) Down syndrome mouse model, which is a widely studied DS mouse model (45, 46) that carries a segment with ~120 genes homologous to Hsa21 (starting upstream of Mrpl39 to the telomeric end of Mmu16), translocated to a small centromeric part of Mmu17 (47–49). The gene discussed is MRPL39; the disease is Dravet syndrome.