Jan 25 (Reuters) - PTC Therapeutics said on Thursday the European health regulator's advisory panel has issued a negative opinion for its drug to treat an inherited progressive muscle-wasting disorder, sending its shares down nearly 12% in extended trading.

The drug, Translarna, is designed to treat Duchenne muscular dystrophy (DMD), a genetic disorder that causes muscle degeneration and almost always affects young boys. The drug had received conditional approval in the European Union in 2014 to treat children aged five years and older who can walk.

The negative opinion issued by the Committee for Medicinal Products for Human Use (CHMP) will result in the withdrawal of the therapy in Europe, the company said.

Conditional marketing authorization of a drug allows for the marketing of medicines designed to treat life-threatening diseases that have few or no treatment options, even if comprehensive clinical data is not yet available.

DMD affects an estimated one in 3,500 male births worldwide, according to the National Organization for Rare Disorders. (Reporting by Mariam Sunny in Bengaluru; Editing by Krishna Chandra Eluri and Shilpi Majumdar)