Zebrafish boc is expressed in the central nervous system and the pharyngeal arches during embryogenesis, and boc mutant fish display axon guidance and forebrain patterning defects and craniofacial cartilage anomalies that include enlarged lower jaws.[17] Microinjection of mRNA encoding wild‐type (WT) BOC into zebrafish embryos resulted in curved and shortened body axes and a broad spectrum of craniofacial defects, including microcephaly, microphthalmia, and anophthalmia. Here, BOC is linked to microcephaly.