MED23 and microcephaly: Med23 has been shown to be important for gene expression and tissue development in C. elegans, Drosophila, zebrafish and mouse embryos (Singh and Han, 1995; Stevens et al., 2002; Kim and Lis, 2005; Wang et al., 2005, 2009; Yin and Wang, 2014; Liu et al., 2016), and interestingly, mutations in MED23 in humans have been linked to intellectual disability, microcephaly and cardiovascular anomalies together with overall growth retardation defects (Lüneburg et al., 2014; Lionel et al., 2016; Hashemi-Gorji et al., 2019).