Finally, as anticipated2, 6, normal cognition, absence of seizures and abducens nerve palsy, and normal brain and brainstem imaging shared by the MYMK-CFZS individuals in this report suggest that many cases previously reported to be CFZS likely represent different disease entities2, 3, 4, 5, 6, 7. Here, MYMK is linked to abducens nerve palsy.