Injection of wild-type fertilized oocytes with an antisense morpholino oligonucleotide (MO) designed to interfere with rrp7a mRNA splicing resulted in phenotypes similar to the rrp7a−/− mutants, supporting that the microcephaly phenotype in mutants is specific to rrp7a (Supplementary Fig. 6e–g). The gene discussed is RRP7A; the disease is microcephaly.