FRMD7 and Nystagmus: Mutations in the FRMD7 gene are the cause of FRMD7-related infantile nystagmus (FIN), which is an X-linked disorder characterized by either the onset of horizontal, conjugate, gaze-dependent nystagmus in the first six months of life, or periodic alternating nystagmus.36 Patients with FIN often present with structurally normal eyes, good visual acuity, and normal colour vision.37