Diagnosis and Treatment

Diagnosis

Concerned couples and individuals can be tested for Gaucher disease. Testing is done by blood sample analysis wherein the level of enzyme responsible for Gaucher disease is measured and the Gaucher gene itself is analyzed at the molecular level.

Individuals who are carriers have an enzyme level that is intermediate between that of affected patients and that of non-carrier individuals. Affected individuals have two Gaucher genes and therefore have very low enzyme levels. Because an overlap exists in the range of enzyme activity values between non-carriers and Gaucher disease carriers, enzyme testing alone as a means of carrier identification is only about 90 percent accurate. Use of direct genetic testing or molecular DNA analysis has provided increased (>98 percent) reliability and accuracy to testing.

Prenatal Diagnosis

All types of Gaucher disease can be detected during pregnancy through procedures known as "amniocentesis" or "chorionic villus sampling." Prenatal diagnosis is available for couples who are at risk for having a child with Gaucher disease. Amniocentesis involves the insertion of a needle through the abdominal wall and uterus into the amniotic sac surrounding the fetus. A small amount of amniotic fluid is removed. This fluid, of fetal origin, contains fetal cells that can be grown in the laboratory. Alternatively, a sample of the developing placenta can be obtained and grown in the laboratory or studied directly. This procedure is called "chorionic villus sampling" ("cvs"). When sufficient numbers of cells have grown (approximately two to four weeks), they are studied biochemically and by DNA techniques. By measuring the level of acid beta-glucosidase in these fetal cells, it can be determined whether or not the fetus has Gaucher disease.

Treatment

The goal for management of Gaucher disease has been supportive and aimed at minimizing future clinical complications. Management initially involves careful monitoring of blood-cell values and orthopedic problems and appropriate medical intervention when problems develop. The laboratory and radiologic findings must then be correlated with the patient's general well-being, as assessed by a comprehensive physical examination.

Enzyme replacement therapy recently has been made available to combat and treat directly the underlying problem in Gaucher disease. Originally, the enzyme was placentally derived (Ceredase ®). However, since 1994, Cerezyme ®, a recombinant form of acid beta-glucosidose, has been approved by the FDA for the treatment of symptomatic Gaucher disease. Several clinical studies have demonstrated the safety and efficacy of both enzyme preparations in reversing the clinical manifestations of Gaucher disease. The therapy entails the regular intravenous infusion of the enzyme, which has been biochemically modified to target the Gaucher cell specifically. In conjunction with coordinated management of Gaucher disease manifestations and complications, this therapy can lead to a greater improved quality of life for affected patients and families.

Decisions regarding enzyme replacement therapy are complicated not only by the fact that the minimal effective dose and optimal frequency of enzyme administration have not been established but also by the extreme variability of clinical manifestations among patients, the expense of therapy, and the required commitment on the part of the patient to regular intravenous administration of the enzyme. Therefore, careful and coordinated management by physicians with special expertise in Gaucher disease is required to tailor each individual's treatment program in order to maximize benefit and well-being.