Costeff syndrome Overview Costeff syndrome, also known as 3-methylglutaconic aciduria type III, is a rare inherited metabolic and neuro-ophthalmological disorder characterized by early-onset vision loss due to optic nerve degeneration, followed later by movement difficulties. Symptoms Vision Symptoms • Optic atrophy: Worsening vision and loss of visual acuity starting in infancy or early childhood. • Nystagmus: Fast, involuntary eye movements. • Strabismus: Eyes that do not line up or look in the same direction. Movement and Neurological Symptoms • Chorea: Involuntary, unpredictable body movements starting in late childhood. • Ataxia: Poor muscle control and balance issues. • Spasticity: Stiff muscles and tight reflexes (spastic paraparesis) that can worsen over time. • Delayed milestones: Late walking or delayed motor skill development. • Dysarthria : Difficulty speaking clearly. Other Signs • Cognitive impact: Many individuals have normal intelligence, though some experience mi...