Gaucher disease

What is Gaucher Disease?

Gaucher disease is an inherited lysosomal storage disorder caused by harmful genetic changes in the GBA1 gene, formerly known as the GBA gene. The condition develops when the body fails to properly produce a particular enzyme to break down a fatty substance called glucocerebroside. Without this enzyme, glucocerebroside and several other associated substances will build up in the body, causing a variety of symptoms.

There are five main types of Gaucher disease, each with different manifestations. These types are described below.

Type 1 Form

Type 1 Gaucher disease is the most common form. It can affect individuals at any age, and its symptoms vary widely from mild to severe.

Many individuals with type 1 Gaucher disease have symptoms related to their bones. Symptoms may include bone pain, low bone mineral density, and increased fracture risk. On the mild end of the spectrum, individuals experience only slightly decreased bone mineral density. In more severe cases, the blood supply to the bones is lost, leading to permanent damage. Bone problems are often the most debilitating aspect of the disease.

Individuals with type 1 Gaucher disease often have an enlarged liver and spleen. They may also have a lowered number of red blood cells (anemia) and platelets. This typically results in patients feeling tired and weak. Fewer platelets in the blood make the individual more prone to bruising and excessive bleeding. Lung disease is another possible symptom.

Type 1 is distinct from other forms of Gaucher disease because it usually does not affect an individual's brain or spinal cord.

Type 2 Form

Type 2 is the infantile or acute neuropathic form of Gaucher disease. Symptoms usually appear before age two and progress rapidly. Like individuals with type 1 Gaucher disease, children with type 2 Gaucher disease may have an enlarged liver and spleen, a lowered number of red blood cells (anemia) leading to weakness and tiredness, a lowered number of platelets leading to bleeding and bruising, and lung disease.

While type 2 Gaucher disease does not cause bone problems, it does cause neurological problems. Neurological symptoms often include developmental delay and intellectual disability. Brainstem abnormalities can cause breathing problems and difficulty swallowing, constant arching of the back and tilting back of the head, uncontrollable tightening and releasing of the muscles, and an inability to open the mouth. As the nervous system deteriorates, children with type 2 Gaucher disease may develop dementia and the inability to coordinate their movements.

Type 3 Form

Type 3 Gaucher disease is known as the juvenile or chronic neuropathic form. Symptoms often begin before age two, though this is variable. The symptoms associated with type 3 Gaucher disease usually progress more slowly than with type 2 Gaucher disease.

Like individuals with type 1 Gaucher disease, children with type 3 Gaucher disease may have an enlarged liver and spleen; lung disease; a lowered number of red blood cells (anemia) leading to weakness and tiredness; and a reduced number of platelets leading to bleeding and bruising. They may also experience bone problems, including pain, fractures, and arthritis.

As with type 2 Gaucher disease, type 3 Gaucher disease also causes neurological problems, including seizures that worsen over time, progressive cognitive issues, and difficulty controlling eye movement. Toward the end of their lives, individuals with type 3 Gaucher disease may also develop dementia.

Perinatal-Lethal Form

The perinatal-lethal form is a rare but severe form of Gaucher disease. This form usually leads to death in utero or shortly after birth. Infants with this disease have symptoms including an enlarged liver and spleen, a lowered number of red blood cells (anemia) and platelets, neurological problems, skin abnormalities, and distinct facial features.

Cardiovascular Form

The cardiovascular form of Gaucher disease causes symptoms involving the heart, notably a hardening of the mitral and aortic valves. If this symptom is severe, heart valve replacement may be required. Also, individuals with the cardiovascular form may have a slightly enlarged liver and spleen; bone problems including pain, fractures, and arthritis; difficulty controlling eye movement; and a clouding of the eye's cornea, which can affect vision. The cardiovascular form of the disease is sometimes called type 3C.

Additional Considerations for Carriers

Studies have shown that carriers of Gaucher disease may have an increased risk of developing Parkinson's disease, above the risks seen in the general population. This risk could be between 7 and 15% by age 80 (in comparison to the general population risk of 1 to 2%). However, most carriers of Gaucher disease never develop Parkinson's disease.

How common is Gaucher Disease?

The incidence of Gaucher disease is 1 in 40,000 to 1 in 60,000 in the general population. It is more common in people of Ashkenazi Jewish ancestry, where the incidence is approximately 1 in 800.

How is Gaucher Disease treated?

Treatment for Gaucher disease involves enzyme replacement therapy (ERT) and substrate reduction therapy. ERT is given by infusion and helps eliminate the buildup of glucocerebrosides in the body. Oral forms of ERT are also available. For many affected individuals, ERT effectively treats disease symptoms and prevents complications, particularly bone and organ damage. ERT does not improve or prevent the neurological symptoms of type 2 and type 3 Gaucher disease.

Individuals with the cardiovascular form of Gaucher disease often need heart valve replacements, after which ERT can be helpful.

Additional treatments for the symptoms of Gaucher disease include blood transfusions for tiredness and excessive bleeding, joint replacement to relieve pain and restore movement, and medication to treat bone pain.

What is the prognosis for an individual with Gaucher Disease?

Because symptoms of Gaucher disease vary widely in type and severity among individuals with the same subtype, the prognosis is also similarly varied. The prognosis for an individual with Gaucher disease depends on the type of Gaucher disease, the severity of symptoms in that particular individual, and the availability and effectiveness of treatment.

Those with a milder form of type 1 Gaucher disease are expected to have a normal lifespan, particularly if ERT is administered when necessary. Some individuals with severe cases of type 1 Gaucher disease may have debilitating symptoms that are more difficult to manage.

Those with type 2 Gaucher disease often have significant developmental delays and die between the ages of two and four. In the most severe type 2 Gaucher disease cases, death may occur before or shortly after birth.

People with type 3 Gaucher disease usually develop symptoms in childhood that slowly worsen over time. While some type 3 Gaucher disease patients have died in childhood, others have lived into their thirties and forties.

Women with milder cases of Gaucher disease can have successful pregnancies.

For those with the cardiovascular form of the disease, the prognosis depends upon the success of their valve replacement surgery.

With the perinatal-lethal form, death occurs before or shortly after birth.

Some individuals affected with Gaucher disease may also develop Parkinson's disease or Lewy body dementia, but most individuals with Gaucher disease never develop these conditions.