Similar to the previously published colgate (hdac1) mutant (Henion et al., 1996; Ignatius et al., 2008), homozygous mutant hdac1Δ4/Δ4 are also larval lethal, and at 3 dpf show a reduced body size, curved trunk, microcephaly and coloboma in the retina (Fig. 5F, arrow). Here, HDAC1 is linked to microcephaly.