Taysha IPO Presentation Deck

Residual Hex A activity determines the severity of GM2 Small increases in Hex A activity may lead to significant improvements in clinical outcomes and quality of life Infantile onset is the most severe form of GM2 - Infantile forms may die within the first 4 years of life, and juvenile onset patients rarely survive beyond mid- teens Infantile (onset < 6 months) - Startle response Hypotonia Cherry-red macula Seizures . Macrocephaly - Progressive visual loss - Death 3-5 years <0.1% F. Juvenile (onset 1.5-5 years) - Cerebellar ataxia Decreased cognition -Progressive weakness Visual loss - Seizures - Death in mid-teens Early adulthood onset - Progressive weakness Cerebellar ataxia - * Normal life span 0.50% 2-4% Residual Hex A Enzyme Activity Psychosis Decreased cognition Age at death variable, normal life span possible 5-10% 17

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