Finally, since mutations in the human DYRK1A gene in heterozygosity cause primary microcephaly (Courcet et al., 2012) and autism (O'Roak et al., 2012), the phenotype observed here in the Dyrk1a+/− mouse model also provides insights into the aetiology of the neurological alterations associated with haploinsufficient mutations in the DYRK1A gene. The gene discussed is DYRK1A; the disease is Primary microcephaly.