Genzyme Corporation (Nasdaq: GENZ) announced today the commercial availability of cystic fibrosis (CF) gene sequencing, a new diagnostic test that can detect approximately 98 percent of the more than 1,200 disease-causing mutations in the CFTR gene. Mutations in the CFTR gene can cause CF, as well as other health issues such as pancreatitis and male infertility. According to the Cystic Fibrosis Foundation, more than 10 million Americans are carriers of CF gene mutations.

"Our new test will help physicians identify a greater number of patients that are impacted by CFTR-related diseases, and who otherwise may not have been diagnosed," said Mara Aspinall, president of Genzyme Genetics, the business unit of Genzyme Corp. focused on the research, development and provision of complex testing services. "When you combine our CF gene sequencing test with access to our knowledgeable geneticists, we help physicians provide better, more informed care for their patients."

Most genetic CF testing is performed by mutation panels, which detect the most common CFTR mutations. CF gene sequencing detects the most common mutations, as well as less common mutations not included in the available mutation panels.

Genzyme Genetics has been a leader in CF testing for more than fifteen years, continually advancing testing by detecting more disease-causing mutations and reducing testing turnaround times to get results to patients faster. Genzyme's full CF gene sequencing test is a direct sequence analysis of the CFTR gene.

Partial CFTR gene sequencing is also available for families with known mutations not detectable in a general screening assay. The new test can be performed on conventional samples, such as blood and prenatal specimens including amniotic fluid and chorionic villi sampling (CVS). In addition, Genzyme offers the new test on blood spot samples, a convenient alternative that collects blood from a fingerstick, and does not require phlebotomy services.

A Comprehensive CF Program

Genzyme Genetics offers a robust CF testing program that offers informative results and access to genetics expertise. The program includes CFplus(TM), an analysis of 97 mutations that provides high CF detection rates for the pan-ethnic U.S. population in just five to eight days. This test is available on blood serum, cheekbrush and mouthwash samples. CF gene sequencing offers a more comprehensive answer in two to three weeks. Genzyme also offers physicians access to board-certified clinical molecular geneticists to discuss test results and genetic counselors for patients to discuss what testing means for them.

About Cystic Fibrosis (CF)

Approximately 30,000 people in the United States are living with CF, according to the Cystic Fibrosis Foundation. CF occurs at increased frequency in Caucasians and individuals of Ashkenazi Jewish descent, but can occur in any ethnic group. It is a disorder of mucus production, primarily affecting the pulmonary, gastrointestinal and reproductive systems. Although there is some variability of clinical expression, most individuals with CF require lifelong medical care and experience reduced life expectancy.

Couples who are planning a pregnancy or who are already pregnant may decide to have testing to find out if they are carriers and at risk of having a baby with CF. It is standard of care to offer carrier screening for CF to Caucasian and Ashkenazi Jewish individuals and to inform couples of other ethnic backgrounds of CF testing. If both parents are found to be carriers, prenatal diagnosis by CVS or amniocentesis is available.

About Genzyme Genetics

Genzyme Genetics is a leading, nationwide provider of high-quality, complex testing services for physicians and their patients. With CLIA- certified laboratories and counseling facilities located across the U.S., Genzyme Genetics offers extensive diagnostic testing services, supported by innovative technology and a commitment to quality service and trusted information. Genzyme Genetics is a business unit of Genzyme Corporation.

About Genzyme

One of the world's leading biotechnology companies, Genzyme is dedicated to making a major positive impact on the lives of people with serious diseases. This year marks the 25th anniversary of Genzyme's founding. Since 1981, the company has grown from a small start-up to a diversified enterprise with more than 8,500 employees in locations spanning the globe and 2005 revenues of $2.7 billion. Genzyme has been selected by FORTUNE as one of the "100 Best Companies to Work for" in the United States.

With many established products and services helping patients in more than 80 countries, Genzyme is a leader in the effort to develop and apply the most advanced technologies in the life sciences. The company's products and services are focused on rare inherited disorders, kidney disease, orthopaedics, cancer, transplant and immune diseases, and diagnostic testing. Genzyme's commitment to innovation continues today with a substantial development program focused on these fields, as well as heart disease and other areas of unmet medical need.

This press release contains forward-looking statements, including the statements regarding the ability of CF gene sequencing to detect approximately 98 percent of the more than 1,200 disease-causing mutations in the CFTR gene and to help physicians identify a greater number of patients that are impacted by CFTR-related diseases. These statements are subject to risks and uncertainties that could cause actual results to differ materially from those projected in these forward-looking statements. These risks and uncertainties include, among others, the failure of CF gene sequencing to produce diagnostic results as anticipated, the inability for physicians to identify a greater number of patients impacted by CFTR-related diseases as expected notwithstanding physicians' access to CF gene sequencing, the continued availability of CF gene sequencing resulting from the lack of commercial acceptance of CF gene sequencing, including the acceptance of the tests at price levels that are economically viable for Genzyme Genetics, and the risks and uncertainties described in reports filed by Genzyme with the Securities and Exchange Commission under the Securities Exchange Act of 1934, as amended, including without limitation the information under the heading "Factors Affecting Future Operating Results" in the Management's Discussion and Analysis of Financial Condition and Results of Operations section of the Genzyme Quarterly Report on Form 10-Q for the quarter ending June 30, 2006. Genzyme cautions investors not to place substantial reliance on the forward- looking statements contained in this press release. These statements speak only as of the date of this press release, and Genzyme undertakes no obligation to update or revise the statements.

Genzyme(R) is a registered trademark and CFplus(TM) is a trademark of Genzyme Corporation. All rights reserved.

Genzyme Corporation
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