** Shares of Stoke Therapeutics STOK.O rise 12.6% to $12.88

** The biotech says it has received U.S. FDA's "breakthrough therapy designation" for zorevunersen, its experimental drug for epileptic disorder Dravet Syndrome

** The FDA's tag is meant to speed up development and review of drugs to treat a serious condition or unmet medical need

** Breakthrough designation seems appropriate given disease modifying potential in a field of symptomatic treatments, brokerage BTIG says

** If approved, the drug could become the first disease modifying treatment for the disease

** Including session's moves, stock up 143.54% YTD

(Reporting by Puyaan Singh)

((Puyaan.Singh@thomsonreuters.com;))