Gillespie syndrome Overview Gillespie syndrome is an ultra-rare genetic disorder defined by a classic triad of partial aniridia (missing parts of the iris), cerebellar ataxia (balance and coordination problems), and mild to moderate intellectual disability. Symptoms Eye (Ocular) Symptoms Partial aniridia: Underdevelopment or partial absence of the colored part of the eye (iris) in both eyes. Scalloped pupils: A unique, uneven scalloped pattern at the inner edge of the iris. Fixed dilated pupils: Enlarged pupils that do not constrict when exposed to light. Photophobia : Increased sensitivity to light.Nystagmus: Rapid, involuntary eye movements Reduced visual acuity : Blurry vision. Balance and Movement (Neurological) Symptoms Cerebellar ataxia : Poor balance, lack of coordination, and an unsteady gait (walking pattern) caused by underdevelopment of the cerebellum. Congenital hypotonia: Weak muscle tone present from birth. Motor delay : Late achievement of developmental milestones, s...