SEMA3F encodes a semaphorin involved in axon guidance.46 Similar to proband ENG_CMK who had CFEOM, developmental delay, sensorineural hearing impairment, and an MRI revealing small CN3 (and inability to resolve CN4), absent CN8, and brain malformations, Sema3f−/− mice have CN3 defasciculation and CN4 absence consistent with CFEOM, as well as hearing impairment and brain malformations.33,34 Although our zebrafish LOF models also had CN3 defasciculation, CN4 was grossly intact, suggesting that this phenotype may have species-specific differences (Supplementary Table 5). The gene discussed is SEMA3F; the disease is congenital fibrosis of the extraocular muscles.