Type I Gaucher's disease is an
autosomal recessive disorder; parents are generally healthy carriers with one functional and one mutated (nonfunctioning) copy of the Gaucher disease gene,
GBA. People with type I Gaucher have a defect in the enzyme called
glucocerebrosidase (also known as acid β-glucosidase). Glucocerebrosidase is an
enzyme, and its function is to convert
glucocerebroside (also known as
glucosylceramide) into ceramide and glucose. When this enzyme doesn't work, glucocerebroside accumulates, which in turn causes liver and spleen enlargement, changes in the bone marrow and blood, and bone disease. Miglustat functions as a competitive and reversible inhibitor of the enzyme glucosylceramide synthase, the initial enzyme in a series of reactions which results in the synthesis of most glycosphingolipids. Earlier treatments on the market (
imiglucerase (approved in 1995),
velaglucerase (approved in 2010),
taliglucerase alfa (Elelyso) (approved in 2012)) are
enzyme replacement therapy—they are functioning versions of the enzyme that doesn't work. Miglustat, on the other hand, prevents the formation of the substance that builds up when the enzyme doesn't work; this is called
substrate reduction therapy. ==Chemistry==