* FDA asks Protalix to speed access to Gaucher drug

* FDA says Protalix drug meets expanded access criteria

* FDA action to offset likely shortages of Genzyme drug

* Protalix shares up 8 percent (Updates with comment from analyst, Protalix, Genzyme)

By Toni Clarke

BOSTON, July 6 (Reuters) - The U.S. Food and Drug Administration is moving to speed up access to experimental drugs for Gaucher disease to help offset likely shortages of Cerezyme, the top-selling drug made by Genzyme Corp (GENZ.O: Quote, Profile, Research).

Biotechnology company Protalix BioTherapeutics Inc (PLX.A: Quote, Profile, Research) and Shire Plc (SHP.L: Quote, Profile, Research)(SHPGY.O: Quote, Profile, Research) said on Monday they have been approached by the FDA to expand access to their experimental drugs for the rare but serious disorder.

Patients with Gaucher are deficient in an enzyme that breaks down a certain type of fat molecule. Fatty cells accumulate in different parts of the body, including the spleen, liver and bone marrow.

The shares of Protalix, which is based in Israel, rose 8.2 percent to close at $4.88 on the American Stock Exchange. Genzyme's shares were up 30 cents, or 0.6 percent, at $55.05. Shire stock rose 1.8 percent to end at $41.03.