In 1934, the French chemist A. Aghion discovered the chemical cause of the enlarged spleens and liver: a buildup of a lipid (fatty substance) called "glucocerebroside."

This discovery led researchers to speculate why there was too much lipid - did people with Gaucher disease make too much of the lipid for their bodies to handle? Or did their bodies not break it down and dispose of it? The answer to this question came during the early 1960s, when Dr. Roscoe Brady's group showed that people with Gaucher disease made the lipid normally but did not make enough of the enzyme "glucocerebrosidase" to break it down and clear it out of the body.

In 1967, Brady's group developed a convenient diagnostic test for Gaucher disease which works by measuring the activity of the enzyme glucocerebrosidase in white blood cells. The amount of enzyme one's body makes directly relates to how severe a case of Gaucher disease one has. The enzyme activity is also one way that may help to distinguish the three types of Gaucher disease described in this chart.

Enlarged cells in the spleen of a person with Gaucher Disease