The common feature of these disorders is congenital dysplasia of the cranial nerves related to ocular movement, which is usually caused by gene mutations of KIF21A, PHOXA, and TUBB3 in CFEOM; CHN1 in DRS; and ROBO3 in HGPPS (6–9). Here, KIF21A is linked to congenital fibrosis of the extraocular muscles.