Gaucher disease is a serious, heritable disorder that can affect many organs and tissues. The signs and symptoms of the disease vary widely among affected individuals, and several types of Gaucher disease have been described.
Causes of Gaucher disease
Gaucher disease is caused by mutations in a gene called GBA, which provides the instructions to make an enzyme called beta-glucocerebrosidase. This enzyme acts within cells to break down a fatty component of cell membranes called glucocerebroside. Mutations in GBA cause the enzyme to be made incorrectly (or not at all) leading to a buildup of glucocerebroside, which is toxic for cells.
Inheritance of Gaucher disease
Gaucher disease is inherited in an autosomal recessive manner — patients must inherit two copies of the mutated gene, one from each parent to develop the disease. An individual therefore only develops the disease if both parents have a copy of the mutation themselves or are so-called carriers of the disease, but do not display any symptoms. If both parents are carriers, their children have a 1 in 4 chance of inheriting the disease, and a 1 in 2 chance of being carriers themselves. They have a 1 in 4 chance of neither developing the disease nor being carriers.
Physicians use the medical history of the patient’s family, as well as symptoms, to diagnose Gaucher disease. If they suspect a patient has Gaucher disease, they will confirm the diagnosis by genetic testing looking for mutations in the GBA gene. For a genetic test, a blood sample is collected from the patient in a hospital or clinic and sent for analysis. The results are returned to the patient’s physician four to six weeks later. The physician then meets with the patient and his or her caregivers to discuss the results and treatment options.
There is currently no cure for Gaucher disease; however, there are therapies available to treat some forms of the disease.
Enzyme replacement therapy, where the patient is given active beta-glucocerebrosidase enzyme, is only effective at treating non-neuronal symptoms of the disease since the enzyme cannot cross the blood-brain barrier. These therapies include: Cerezyme (imiglucerase), VPRIV (velaglucerase alfa), and Elelyso (taliglucerase alfa).
Substrate reduction therapy inhibits the metabolic step of generating glucocerebroside (the cell membrane component that is broken down by beta-glucocerebrosidase). By reducing the enzyme’s substrate, the waste products that are produced due to the absence of the enzyme are also reduced. Substrate reduction therapy has only been approved to treat type 1 Gaucher disease, and includes Cerdelga (eliglustat) and Zavesca (miglustat).