Gaucher Disease

Gaucher disease is a genetic condition.

Gaucher disease (sometimes called Gaucher's disease) is an inherited condition that results in the abnormal accumulation of fatty substances known as glycolipids in different body tissues due to a deficiency of an enzyme known as glucocerebrosidase. There are several different types of the condition and the signs and symptoms that arise from sphingolipid accumulation vary widely.

Gaucher disease is due to a genetic defect in a gene known as GBA1. It belongs to a class of diseases called lysosomal storage diseases, named after a type of cell affected by the buildup of glycolipids.

Gaucher disease has been referred to in the medical literature by several different names, such as:

• Cerebroside lipidosis syndrome
• Gaucher splenomegaly
• Gaucher syndrome
• Gaucher's disease
• Gauchers disease
• GD
• Glucocerebrosidase deficiency
• Glucocerebrosidosis
• Glucosyl cerebroside lipidosis
• Glucosylceramidase deficiency
• Glucosylceramide beta-glucosidase deficiency
• Glucosylceramide lipidosis
• Kerasin histiocytosis
• Kerasin lipoidosis
• Kerasin thesaurismosis
• Lipoid histiocytosis (kerasin type)

Type 1 Gaucher disease

The most common form of the condition is type 1 Gaucher disease. About 90% of people with the condition have this type. The signs and symptoms of this type can vary in their extent of severity. The symptoms can appear in childhood or may be delayed until adulthood. The brain and spinal cord, or central nervous system (CNS), are typically not affected by the disease, so this type is sometimes referred to as non-neuronopathic, meaning that the condition does not affect nerve cells.

Type 2 Gaucher disease (acute neuronopathic form)

This rare type of Gaucher disease affects the nervous system and is termed neuronopathic Gaucher disease. Signs and symptoms include seizures, eye movement problems, and brain damage. Type 2 Gaucher disease is very severe and typically leads to life-threatening medical problems that begin in infancy.

Type 3 Gaucher disease (chronic neuronopathic form)

Like Type 2 Gaucher disease, type 3 Gaucher is a neuronopathic form of Gaucher disease that affects the nervous system, but symptoms do not progress as rapidly as in Type 2. The signs and symptoms may appear in infancy or later in childhood.

Perinatal lethal Gaucher disease

Perinatal lethal Gaucher disease is the most severe form of the condition. With this type, life-threatening conditions can appear before birth. There may be excessive swelling and fluid accumulation in the fetus (hydrops fetalis) before birth. Other features can include severe neurological disturbances, abnormal facial features, hepatosplenomegaly, and dry or scaly skin. Most infants with this form of the condition survive only a few days after birth.

Cardiovascular Gaucher disease

This type of Gaucher disease, considered a rare subgroup of type 3 disease, primarily affects the heart, leading to calcification or hardening of the heart valves. Sometimes, symptoms and signs of other types of Gaucher disease may also be present.

All of the types of Gaucher disease are caused by a deficiency of the enzyme glucocerebrosidase, leading to an abnormal buildup of fatty substances, glycolipids, in the body cells. Mutations in the gene known as GBA1 are the cause of the deficient enzyme, and over 300 different GBA1 mutations have been identified in people with Gaucher disease. The mutations are inherited (passed from parent to offspring) in an autosomal recessive manner (see above).

• The four most common mutations of the GBA1 gene are N370S, L444P, 84gg, and IVS2[+1].
• DNA analysis for these 4 mutations can detect 90%-95% of the mutations associated with Gaucher Disease in the Ashkenazi Jewish population, and 50%-75% of the associated mutations in the general population.

Gaucher disease is inherited in an autosomal recessive pattern, meaning that both parents must carry a copy of the defective gene for a child to be affected.

In people of Ashkenazi Jewish descent Type 1 Gaucher disease (see below) is more common and affects 1 out of every 855 people. About 1 out of every 15 people of Ashkenazi Jewish descent are thought to be carriers of the genetic mutation responsible for Gaucher disease. The other types of Gaucher disease do not occur more frequently in people of Ashkenazi Jewish heritage.

In the non-Jewish population, Gaucher disease affects 1 out of every 40,000 people.

The main signs and symptoms of Gaucher disease include the following:

• Anemia (low red blood cell count)
• Fatigue (tiredness)
• Low platelet count can lead to easy bruising
• Enlarged spleen and liver (hepatosplenomegaly)
• Enlarged Liver
• Lung problems
• Eye movement disorders
• Yellow spots in the eyes
• Easy bleeding that is difficult to stop
• Bone pain, bone crisis (severe bone pain often accompanied by fever), and the chance of easily broken bones

People with type 1 Gaucher disease usually first notice painless enlargement of the spleen, anemia, or bleeding and bruising due to low platelet count. The enlargement of the spleen may become severe and may limit a child's growth due to the energy required to sustain the enlarging spleen. An enlarged liver and abnormal liver function tests are also characteristic signs. Skeletal involvement by Gaucher disease is common and can take the form of bone pain, fractures of bone, and a defect of the thigh bone (femur).

Patients with Gaucher disease may be treated by several different medical specialists, depending on the type of the disease and the specific symptoms and signs of the condition they experience. These may include:

• Pediatricians
• Neonatologists
• Internists
• Geneticists
• Neurologists
• Orthopedists
• Critical care specialists
• Cardiologists
• Hematologists

Most patients who are treated with enzyme replacement therapy will have their treatment plan managed by a geneticist and/or hematologist.

A blood test is used to make the diagnosis of Gaucher disease.

• The enzyme assay test measures the activity of the glucocerebrosidase enzyme in certain white blood cells. Having less than 15% of normal enzyme activity is diagnostic for Gaucher disease.
• Genetic analysis is also done to establish the specific type of mutations in the GBA1 gene.

There is no cure for Gaucher disease, but medical treatments are available. Enzyme replacement therapy (ERT) is the primary form of treatment for people with type 1 and Gaucher disease and for the non-neurologic symptoms of type 3 Gaucher disease. The drug is given intravenously, generally at 2-week intervals. There are three ERT drugs available, imiglucerase (Cerezyme), velaglucerase alfa (VPRIV), and taliglucerase alfa (Elelyso).

Other medications available to treat Gaucher disease include drugs that block the production of the sphingolipids that accumulate in cells and cause symptoms. These drugs are known as glucosylceramide synthase inhibitors and are taken by mouth. Two drugs in this class are miglustat (Zavesca) and eliglustat (Cerdelga).

Formerly, the condition was often treated by surgical removal of the spleen (splenectomy). However, this is typically not necessary given the availability of ERT.

The prognosis for people with type 1 or type 3 Gaucher disease who receive treatment is very good. Many people with Gaucher disease have few symptoms and can expect a normal lifespan even without treatment.

• One study estimated life expectancy at birth for people with type 1 Gaucher disease to be 68 years, compared with 77 years in the general population.
• Type 2 Gaucher disease usually results in death within the first few years of life.

As with any inherited disease, sharing information with family members is important. If Gaucher disease is identified within a family, other family members may wish to be tested to find out if they are carriers for the gene mutation. Carrier testing is simple and can be performed on a sample of blood or saliva. Your healthcare professional can help you decide if carrier testing is appropriate and may refer you to a genetic counselor for more information.

Living with Gaucher disease or any chronic illness is stressful for both patient and family. Getting help and support are important for achieving the best quality of life possible while facing the challenges that the illness brings. The National Gaucher Foundation (800-504-3189) offers educational and support services for affected families, including a mentor program, an electronic pen pal program for young adults, real-life patient stories, and numerous educational programs.