Exhibit 99.1

CONTACTS:
For BioMarin                                         For Genzyme
Joshua Grass (investors)                             Sally Curley (investors)
(415) 884-6777                                       (617) 591-7140

Francesca DeVellis (media)                           Dan Quinn (media)
Feinstein Kean Healthcare                            (617) 591-5849
(617) 761-6703


For Immediate Release
May 15, 2003

         Genzyme and BioMarin Announce that Aldurazyme is Now Available

                 in the United States for the Treatment of MPS I

         Cambridge, Mass. and Novato, Cal.- Genzyme General (Nasdaq: GENZ) and
BioMarin Pharmaceutical Inc. (Nasdaq and Swiss SWX New Market: BMRN) announced
today that Aldurazyme(R) (laronidase) is now available in the United States as
the first specific treatment for people with the rare genetic disease
mucopolysaccharidosis I (MPS I). Aldurazyme was approved on April 30, 2003 by
the U.S. Food and Drug Administration, and is being shipped to physicians this
week. Aldurazyme was developed by BioMarin and Genzyme under a joint venture
agreement that assigns commercial manufacturing responsibilities to BioMarin,
and worldwide sales and marketing responsibilities to Genzyme.

         Genzyme has begun to market Aldurazyme to physicians through an
expanded sales force of nearly 40 professionals who specialize in providing
enzyme replacement therapies for rare genetic diseases. Sales efforts will focus
on raising awareness of MPS I and the availability of Aldurazyme among
geneticists, pediatricians, and sub-specialists who are involved in the
multi-disciplinary care of patients with MPS I.


         In preparation for launch, Genzyme has worked with a core network of
hospitals and medical centers to help prepare them to immediately begin treating
patients with Aldurazyme. Many of these centers have extensive experience
treating patients with lysosomal storage diseases, including Gaucher disease,
Fabry disease, and MPS I. Aldurazyme will be distributed in the United States
primarily by Accredo Health, Inc. of Memphis, TN. and TheraCom, Inc. of
Bethesda, MD.

         Genzyme has also begun to track the long-term progress of people with
MPS I through a worldwide patient registry, which was launched last month.

     "Aldurazyme expands the options available to patients and physicians to
address this devastating disease," said David Meeker, M.D., president of
Genzyme's Lysosomal Storage Disorders business unit. "We are well prepared to
rapidly introduce this product to all who need it."

Market Introduction

         Genzyme has extensive resources in place to help ensure that Aldurazyme
is available to all patients who would benefit from it and for whom the product
is indicated. Genzyme Treatment Support links families with on-staff specialists
who help them obtain insurance reimbursement for treatment, and access to local
clinicians who specialize in treating MPS I. Genzyme has also launched
LysoSolutionsSM, a network of programs and services designed to optimize the
delivery of care provided to MPS I patients based on their individual needs.

         It is anticipated that the vast majority of patients receiving
Aldurazyme will have either the Hurler or Hurler-Scheie form of the disease. The
annual cost of treatment will vary considerably according to each individual
patient's weight. The average annual cost of therapy for these patients is
estimated to be comparable to other enzyme replacement therapies currently on
the market.


         Aldurazyme received a positive opinion from the Committee for
Proprietary Medicinal Products (CPMP) in the first quarter of 2003, typically
the final step to marketing clearance in the 15 countries of the European Union.
The companies expect a final decision from the European Commission in the second
quarter of 2003, at which time they will provide sales guidance. Applications to
market Aldurazyme are also pending in Canada and Australia, and the companies
expect a response late in 2003 or early in 2004.

         MPS I is a rare, progressive, heterogeneous, debilitating disease
caused by a deficiency of the enzyme alpha L-iduronidase that affects an
estimated 3,000 to 4,000 people worldwide, including approximately 1,000 in the
United States. Patients who lack this enzyme accumulate a carbohydrate called
glycosaminoglycan (GAG) in tissues and organ systems. A majority of patients die
before adulthood due to a wide range of problems related to the disease,
including progressive damage to the heart, lungs, liver, and kidneys. Aldurazyme
addresses the underlying cause of MPS I by replacing the missing enzyme through
a weekly infusion. More information about MPS I can be found at
http://www.mps1disease.com.

         Aldurazyme is indicated for patients with the Hurler and Hurler-Scheie
forms of MPS I, and for Scheie patients with moderate to severe symptoms. The
risks and benefits of treating mildly affected patients with the Scheie form
have not been established. Aldurazyme has not been evaluated for effects on the
central nervous system manifestations of the disorder. More information on
Aldurazyme can be found at http://www.aldurazyme.com.

         The most common side effects associated with treatment with Aldurazyme
were upper respiratory tract infection, rash, and injection site reaction. The
most common adverse reactions requiring treatment were infusion-related
hypersensitivity reactions including flushing, fever, headache, and rash. The
most serious adverse reaction reported with Aldurazyme was an anaphylactic
reaction consisting of hives and blockage of the breathing tubes, which occurred
in one person. Emergency surgery was required to help this patient breathe. This
patient's underlying disease may have contributed to the severity of this
reaction. The majority of patients in clinical studies developed an immune
response to treatment with Aldurazyme. The clinical significance of this
response is unknown. Aldurazyme is available by prescription only. Full
prescribing information is available at http://www.genzyme.com/corp/AZpi.pdf.


         Genzyme General develops and markets therapeutic products and
diagnostic products and services. Genzyme General has six therapeutic products
on the market and a strong pipeline of therapeutic products in development
focused on the treatment of genetic diseases and other chronic debilitating
disorders with well-defined patient populations. Genzyme General is a division
of Genzyme Corp.

         BioMarin Pharmaceutical specializes in the development and
commercialization of therapeutic enzyme products to treat serious,
life-threatening diseases and conditions.

         This press release contains forward-looking statements, including
without limitation statements about: expectations and plans related to the
commercialization and manufacture of Aldurazyme; estimates concerning the MPS I
patient population, including the prevalence of the different forms of MPS I;
expectations concerning the annual cost of Aldurazyme and plans to provide sales
guidance, including the expected timing thereof; and expectations concerning
decisions by regulatory authorities in the European Union, Canada and Australia
regarding marketing applications for Aldurazyme, including the anticipated
timing thereof. 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 effectiveness of the companies' commercialization plan for Aldurazyme and
Genzyme's sales force; the ability to manufacture sufficient quantities of
product and to do so in a timely and cost efficient manner; the accuracy of the
companies' information concerning the MPS I patient population; the actual
impact of the Committee for Proprietary Medicinal Product's opinion on decisions
made by the European Commission regarding Aldurazyme; the content and actual
timing of decisions by the European Commission and other regulatory authorities
concerning marketing applications, labeling and pricing for Aldurazyme and
manufacturing facilities to be used for Aldurazyme; the ability to maintain
relationships with third party distributors and fill/finish facilities; the
continued funding and operation of the joint venture between Genzyme and
BioMarin; the availability and extent of reimbursement for Aldurazyme from third
party payers; the companies' ability to obtain and maintain adequate patent and
other proprietary rights protection for Aldurazyme; the scope, validity and
enforceability of patents and other proprietary rights held by third parties
related to therapies for MPS I and the actual impact of such patents and other
rights on the companies' ability to commercialize Aldurazyme; and the risks and
uncertainties described in reports filed by Genzyme and BioMarin with the
Securities and Exchange Commission under the Securities Exchange Act of 1934, as
amended, including without limitation the factors contained under the caption
"Factors Affecting Future Operating Results" in Exhibit 99.2 to Genzyme
Corporation's 2002 Annual Report on Form 10-K, as amended. Genzyme General
Division common stock is a series of common stock of Genzyme Corporation.
Therefore, holders of Genzyme General Division common stock are subject to all
of the risks and uncertainties described in Genzyme Corporation reports. Genzyme
and BioMarin caution investors not to place undue 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 and BioMarin
undertake no obligation to update or revise the statements.


         Genzyme(R) is a registered trademark and LysoSolutionsSM is a service
mark of Genzyme Corporation. Aldurazyme(R) is a registered trademark of
BioMarin/Genzyme LLC. All rights reserved.

         BioMarin's press releases and other company information is available at
http://www.biomarinpharm.com. Information on BioMarin's website is not
incorporated by reference into this press release.