Rogerio Vivaldi, MD, vice president and president, Personalized Genetic Health, Genzyme Corporation in Cambridge, Massachusetts, discusses the transformation he has observed in patients with Gaucher disease, a rare genetic disorder in which patients lack an enzyme called glucocerebrosidase. Without the enzyme, harmful substances build up in the liver, spleen, bones, and bone marrow.

Vivaldi recalls visiting with his first patient in Brazil who was diagnosed with the genetic disorder Gaucher disease. This patient was the first patient treated with enzyme replacement therapy in Brazil and had a lasting impact on Vivaldi's life and career.

The treatment at the time was created using a placenta to extract the necessary enzymes. Within the first few months of beginning the therapy the patient was able to lead a normal life, enlargement of the liver and spleen subsided, and his platelet levels returned to normal. Not only did it affect him physiologically but also psychologically; in many ways he became a completely different person.

The experience of how certain medicines could change the course of a disease left a lasting impression on Vivaldi. Enzyme replacement therapy has now been used for 20 years and because of this it is easy to forget how dramatic the benefits of can be.