Gaucher disease is a rare, inherited metabolic disorder in which deficiency of the enzyme glucocerebrosidase results in the accumulation of harmful quantities of certain fats (lipids), specifically the glycolipid glucocerebroside, throughout the body especially within the bone marrow, spleen and liver. The symptoms and physical findings associated with Gaucher disease vary greatly from case to case. Some individuals will develop few or no symptoms (asymptomatic); others may have serious complications. Common manifestations of Gaucher disease include an abnormally enlarged liver and/or spleen (hepatosplenomegaly), low levels of circulating red blood cells (anemia), low levels of platelets(thrombocytopenia), and skeletal abnormalities. Platelets are blood cells that promote clotting and patients with thrombocytopenia may develop bleeding problems. Three separate forms of Gaucher disease have been identified and are distinguished by the absence of, or the presence and extent of, neurological complications. All three forms of Gaucher disease are inherited as autosomal recessive traits.

Gaucher disease is categorized as a lysosomal storage disorder. Lysosomes are the major digestive units in cells. Enzymes within lysosomes break down or "digest" nutrients, including certain complex carbohydrates and fats. In Gaucher disease certain sugar (glucose) containing fat, known as glycolipids, abnormally accumulate in the body because of the lack of the enzyme, glucocerebrosidase. This accumulation or "storage" of lipids leads to the various symptoms or physical findings associated with a lysosomal storage disease. Gaucher disease is the most common type of lysosomal storage disorder.