Recently, mutations in the X chromosome gene OGT were identified as causal for ID, a condition termed OGT congenital disorder of glycosylation (OGT-CDG) (Willems et al., 2017; Pravata et al., 2020b; Pravata et al., 2019; Pravata et al., 2020a; Vaidyanathan et al., 2017). Here, OGT is linked to congenital disorder of glycosylation.