The first one presented an inversion of almost 10 Mb in length affecting EHMT1 (MIM * 607001) in intron 25 of 26 (g:9:130,887,682-140,727,115, hg19) (ERN-ITHACA; Fig. 1C) This subject meets the criteria for Kleefstra syndrome type 1 (KS1) [17], a well-described syndromic neurodevelopmental condition characterized by psychomotor delay, cognitive impairment, behavioral disorders, facial dysmorphism, abnormal skull shape, abnormalities of hands, and congenital heart defects [17, 18]. Here, EHMT1 is linked to Cognitive impairment.