NOTCH3 and snowflake vitreoretinal degeneration: Other frequent features included hyperreflexia (91%, 21/23), strabismus (50%, 9/18), ataxia (48%, 10/21), dysarthria (39%, 7/18), and headache (35%, 8/23), although it could not be conclusively determined if the latter corresponded to migraine, a known feature of NOTCH3-SVD (Table 1, Fig. 3, Supplementary Table S2).