PCDH9 and microcephaly: CDH12 was identified in chickens as a candidate core gene that could control the metatarsus circumference and regulate the traits of chest width and body weight [57]; the unusual expression of PCDH9 in cells could lead to growth delay and microcephaly in humans [58]; SH3BP4 could regulate the growth-factor-regulated mTORC1 pathway, which in turn had an impact on cell growth [59]; USP6NL was primarily implicated in epidermal growth factor in humans [60]; CNTN3 was identified as a candidate gene that relates to the growth of corneal endothelial cells in the New Zealand rabbit [61].