CBS and Dravet syndrome: Noticeably, Cbs, coding for the Cystathionine beta-synthase, another driver gene for DS cognitive phenotypes (59), was found to be downregulated in all the models, except Dp3Yah and Tg(Dyrk1a), suggesting direct control of Cbs transcription by at least two loci, one located in Dp5Yah and another one, not due to Dyrk1a overdosage, in the Dp1Rhr trisomic region.