Typescript also uses 'gradual' typing. See http://siek.blogspot.co.uk/2012/10/is-typescript-gradually-t... - Siek is referenced in the original post, too.
Clojure's type system sounds more powerful than Typescript's though.
Clojure's type system sounds more powerful than Typescript's though.
I guess Typed Clojure is more powerful than Typescript in a few ways, but it's more about how well the type system fits the language. I've never used Typescript, but it seems to fit nicely, with interesting tradeoffs.