Numerous genetics studies have identified pathogenic variants of CACNA1A (Epi, 2016; Luo et al., 2017), CSNK2A1 (Trinh et al., 2017), PPP1CB (Gripp et al., 2016; Ma et al., 2016), PPP2CA (Reijnders et al., 2017), SLC6A1 (Carvill et al., 2015; Halvorsen et al., 2016; Palmer et al., 2016; Yuan et al., 2017), and USP7 (Zarrei et al., 2017) from large cohorts of unrelated patients who presented a wide spectrum of neurological and behavioral phenotypes of global developmental delay, attention deficit disorder, epileptic encephalopathy, macrocephaly, ID or sensory processing disorder. This evidence concerns the gene USP7 and Global developmental delay.