Recent human genetic studies have revealed that deletion of, or non-synonymous mutations in, the MEF2C gene is associated with a severe neurodevelopmental disorder with features of autism and ID (Paciorkowski et al., 2013; Mikhail et al., 2011; Novara et al., 2010; Le Meur et al., 2010; Cardoso et al., 2009; Engels et al., 2009). The gene discussed is MEF2C; the disease is neurodevelopmental disorder.