The Food and Drug Administration on Tuesday approved a new treatment for Gaucher disease, a rare genetic disorder that can cause liver and neurological problems.

The new drug is called Elelyso. It was developed by Protalix BioTherapeutics Inc. and licensed to Pfizer Inc., which is the largest drugmaker in the world in terms of sales. The FDA approved Elelyso as a treatment for type 1 Gaucher disease, and estimated that condition affects about 6,000 people in the U.S. Elelyso is approved as an orphan drug, which means competing versions of the product won’t be approved for up to seven years.

People with Gaucher disease lack an important enzyme, which leads to the dangerous buildup of fatty chemicals in the liver, spleen, bones and nervous system. The FDA said the major signs of the disease include liver and spleen damage, low red blood cell and blood platelet counts, and bone problems. Elelyso, or taliglucerase, is approved as a replacement for that enzyme.

In clinical trials, the most common side effects of treatment with Elelyso included headache, chest pain, weakness, fatigue, hives, skin redness, increase blood pressure, back pain, joint pain, and flushing.

Other drugs used to treat Gaucher disease include Sanofi’s Cerezme and Shire PLC’s Vpriv.

Shares of Protalix BioTherapeutics fell 10.9 percent to $6.19 on Tuesday, and gained $1.22, or 19.7 percent, to $7.41 in aftermarket trading.