Gaucher disease (GD) is a progressive inherited genetic disorder which occurs when a type of large fatty material (glucocerebroside) accumulates to excessive levels in multiple organs and tissues in the body. This is due to a defective enzyme called glucocerebrosidase. The liver, spleen, lungs and bone marrow are the most commonly affected organs. GD is classified into 3 major types. Type 1 GD is the most common form of the disease. Symptoms include an enlarged liver and spleen, a reduced number of red blood cells and platelets, bone abnormalities, and rarely, lung impairment. The brain and spinal cord, however, are usually not affected. The onset of type I GD varies from childhood to adult, and bone diseases have the greatest impact on the quality of life. Treatments are available for individuals who have these symptoms, including enzyme replacement therapy. Type 2 GD is known as the most severe form of the disease. Babies with type 2 GD are normally diagnosed in the newborn period with severe neurological symptoms which progress rapidly and death occurs by age two to four years. Although bone diseases are not present, other features of type 1 GD, as well as additional symptoms including abnormal eye movements, seizures, low muscle tone and brain damage are common in type 2 GD. Type 3 GD also shows neurological symptoms but is milder than type 2. The disease usually develops during childhood with slow progress. Individuals with type 3 GD may experience different combinations of neurological defects as well as symptoms shown in type 1 GD, and usually survive into the third or fourth decade of life. Enzyme replacement therapy is not effective or appropriate for those with type 2 and type 3 GD. Pathogenic variants in the GBA gene cause GD.