ZNHIT3 and Intellectual disability: Homozygous null mutations in zinc finger HIT-type 3 (ZNHIT3) and phosphatidylinositol glycan anchor biosynthesis class W (PIGW) cause encephalopathy (Anttonen et al., 2017) or intellectual disability (Chiyonobu et al., 2014; Hogrebe et al., 2016), respectively.