Timothy syndrome (Monarch Disease Ontology identifier MONDO_0010979) is a multi-system disorder characterized by cardiac, hand, facial and neurodevelopmental features that include QT prolongation, webbed fingers and toes, flattened nasal bridge, low-set ears, small upper jaw, thin upper lip, and characteristic features of autism or autistic spectrum disorders. Also known as: TIMOTHY syndrome, TS, long QT syndrome-syndactyly syndrome.