MIR17 and microcephaly: Simultaneous deletion of Mir17-92 and Mir106b-25 (doubly conditional knockout, Prx1-Cre:Mir17-92fl/fl:Mir106b-25−/−, 17 dKO) caused microcephaly, cutaneous syndactyly, and brachydactyly, phenotypes similar to those observed in patients with Feingold syndrome type 2 (Fig. 1a–d).