CACNA1F and pathologic nystagmus: Hemizygous missense (c.299T>G, p.(Leu100Arg)) and nonsense (c.2905C>T, p.(Arg969Ter)) variants of CACNA1F were identified in NYS-002 and NYS-004, respectively; both patients were male subjects with reduced visual acuity and predominantly horizontal nystagmus with a vertical component.