OGT and cask-related x-linked intellectual disability: Interestingly, recent data has identified placental OGT levels as a biomarker for neurodevelopmental disorders (Howerton et al., 2013; Howerton and Bale, 2014) and mutations in the OGT gene as being causative to a subset of X-linked intellectual disability (XLID) patients (Pravata et al., 2020b).