<PAGE>


                                                               Exhibit 10.18.1


                                                  GENZYME CORPORATION

NOTICE OF GRANT OF STOCK OPTIONS                  ID: 06-1047163
AND OPTION AGREEMENT                              500 Kendall Street
                                                  Cambridge, MA 02142


OPTIONEE NAME                                     OPTION NUMBER:
OPTIONEE ADDRESS                                  PLAN:
                                                  ID:


Effective _________, you have been granted a(n) Incentive Stock Option to buy
_____ shares of GENZYME CORPORATION (the Company) stock at $_______ per share.

The total option price of the shares granted is $_________.

Shares in each period will become fully vested on the date shown.

     Shares               Vest Type              Full Vest           Expiration



                      MAINTAIN THIS COPY FOR YOUR RECORDS.



These options are granted under and governed by the terms and conditions of the
Company's Stock Option plan as amended and the Option Agreement, all of which
are attached and made a part of this document.


                                                                          Date:
                                                                          Time:

<PAGE>


                 GENZYME CORPORATION 2004 EQUITY INCENTIVE PLAN
                               OFFICER (TIER I/II)
                   INCENTIVE STOCK OPTION TERMS AND CONDITIONS

         1. PLAN INCORPORATED BY REFERENCE. THIS STOCK OPTION IS ISSUED PURSUANT
TO THE TERMS OF THE PLAN AND MAY BE AMENDED AS PROVIDED IN THE PLAN. CAPITALIZED
TERMS USED AND NOT OTHERWISE DEFINED IN THIS CERTIFICATE HAVE THE MEANINGS GIVEN
TO THEM IN THE PLAN. THIS CERTIFICATE DOES NOT SET FORTH ALL OF THE TERMS AND
CONDITIONS OF THE PLAN, WHICH ARE INCORPORATED HEREIN BY REFERENCE. COPIES OF
THE PLAN MAY BE OBTAINED UPON WRITTEN REQUEST WITHOUT CHARGE FROM THE
SHAREHOLDER RELATIONS DEPARTMENT OF THE COMPANY.

         2. OPTION PRICE. THE PRICE TO BE PAID FOR EACH SHARE OF STOCK ISSUED
UPON EXERCISE OF THE WHOLE OR ANY PART OF THIS STOCK OPTION IS THE OPTION PRICE
SET FORTH ON THE FACE OF THIS CERTIFICATE (THE "OPTION PRICE").

         3. EXERCISABILITY SCHEDULE. THIS STOCK OPTION MAY BE EXERCISED AT ANY
TIME AND FROM TIME TO TIME UP TO THE NUMBER OF SHARES AND IN ACCORDANCE WITH THE
EXERCISABILITY SCHEDULE SET FORTH ON THE FACE OF THIS CERTIFICATE, BUT ONLY FOR
THE PURCHASE OF WHOLE SHARES. THIS STOCK OPTION MAY NOT BE EXERCISED AS TO ANY
SHARES AFTER THE DATE OF EXPIRATION SET FORTH ON THE FACE OF THIS CERTIFICATE
(THE "EXPIRATION DATE").

         4. METHOD OF EXERCISE. TO EXERCISE THIS STOCK OPTION, THE PARTICIPANT
SHALL DELIVER WRITTEN NOTICE OF EXERCISE TO THE COMPANY SPECIFYING THE NUMBER OF
SHARES WITH RESPECT TO WHICH THE STOCK OPTION IS BEING EXERCISED ACCOMPANIED BY
PAYMENT OF THE OPTION PRICE FOR SUCH SHARES IN CASH, BY CERTIFIED CHECK OR IN
SUCH OTHER FORM, INCLUDING SHARES OF STOCK OF THE COMPANY VALUED AT THEIR FAIR
MARKET VALUE ON THE DATE OF DELIVERY, AS THE ADMINISTRATOR MAY APPROVE. PROMPTLY
FOLLOWING SUCH NOTICE, THE COMPANY WILL DELIVER TO THE PARTICIPANT A CERTIFICATE
REPRESENTING THE NUMBER OF SHARES WITH RESPECT TO WHICH THE STOCK OPTION IS
BEING EXERCISED.

         5. RECAPITALIZATION, MERGERS, ETC. IN THE EVENT OF A COVERED
TRANSACTION, THE ADMINISTRATOR MAY UPON WRITTEN NOTICE TO THE PARTICIPANT
PROVIDE THAT THIS STOCK OPTION SHALL TERMINATE ON A DATE NOT LESS THAN 20 DAYS
AFTER THE DATE OF SUCH NOTICE UNLESS THERETOFORE EXERCISED. IN CONNECTION WITH
SUCH NOTICE, THE ADMINISTRATOR MAY IN ITS DISCRETION ACCELERATE OR WAIVE ANY
DEFERRED EXERCISE PERIOD. [ NOTWITHSTANDING THE FOREGOING, IN THE EVENT OF A
CHANGE IN CONTROL OF THE COMPANY (AS DEFINED IN A VOTE OF THE COMPENSATION
COMMITTEE ADOPTED MAY 29, 2002), THIS STOCK OPTION SHALL BECOME EXERCISABLE
AS TO ALL SHARES WITHOUT REGARD TO ANY DEFERRED EXERCISABILITY SCHEDULE OR
DEFERRED EXERCISE PERIOD.](1)

         6. STOCK OPTION NOT TRANSFERABLE. THIS STOCK OPTION IS NOT TRANSFERABLE
BY THE PARTICIPANT OTHERWISE THAN BY WILL OR THE LAWS OF DESCENT AND
DISTRIBUTION, AND IS EXERCISABLE, DURING THE PARTICIPANT'S LIFETIME, ONLY BY THE
PARTICIPANT. THE NAMING OF A DESIGNATED BENEFICIARY DOES NOT CONSTITUTE A
TRANSFER. A "DESIGNATED BENEFICIARY" MEANS THE BENEFICIARY DESIGNATED BY THE
PARTICIPANT, IN A MANNER DETERMINED BY THE ADMINISTRATOR, TO RECEIVE AMOUNTS DUE
OR EXERCISE RIGHTS OF THE PARTICIPANT IN THE EVENT OF THE PARTICIPANT'S DEATH.
IN THE ABSENCE OF AN EFFECTIVE DESIGNATION BY THE PARTICIPANT, "DESIGNATED
BENEFICIARY" MEANS THE PARTICIPANT'S ESTATE.

         7. EXERCISE OF STOCK OPTION AFTER TERMINATION OF EMPLOYMENT. IF THE
PARTICIPANT'S EMPLOYMENT WITH (a) THE COMPANY, (b) AN AFFILIATE, OR (c) A
CORPORATION (OR PARENT OR SUBSIDIARY CORPORATION OF SUCH CORPORATION) ISSUING OR
ASSUMING A STOCK OPTION IN A TRANSACTION TO WHICH SECTION 424(a) OF THE CODE
APPLIES, IS TERMINATED FOR ANY REASON OTHER THAN BY DISABILITY (WITHIN THE
MEANING OF SECTION 22(e)(3) OF THE CODE), DEATH OR RETIREMENT, THE PARTICIPANT
MAY EXERCISE THE RIGHTS WHICH WERE AVAILABLE TO THE PARTICIPANT AT THE TIME OF
SUCH TERMINATION ONLY WITHIN THREE MONTHS FROM THE DATE OF TERMINATION. IF
PARTICIPANT'S EMPLOYMENT IS TERMINATED AS A RESULT OF DISABILITY, THIS STOCK
OPTION SHALL BECOME EXERCISABLE AS TO ALL SHARES WITHOUT REGARD TO ANY DEFERRED
EXERCISE PERIOD, AND SUCH RIGHTS MAY BE EXERCISED WITHIN TWELVE MONTHS FROM THE
DATE OF TERMINATION. IF PARTICIPANT'S EMPLOYMENT IS TERMINATED AS A RESULT OF
RETIREMENT (WHICH IS DEFINED AS A MINIMUM OF AGE 60 PLUS A MINIMUM OF FIVE YEARS
OF SERVICE), THIS STOCK OPTION SHALL BECOME EXERCISABLE AS TO ALL SHARES WITHOUT
REGARD TO ANY DEFERRED EXERCISE PERIOD, AND SUCH RIGHTS MAY BE EXERCISED WITHIN
THREE YEARS FROM THE DATE OF TERMINATION. UPON THE DEATH OF THE PARTICIPANT,
THIS STOCK OPTION SHALL BECOME EXERCISABLE AS TO ALL SHARES WITHOUT REGARD TO
ANY DEFERRED EXERCISE PERIOD, AND HIS OR HER DESIGNATED BENEFICIARY SHALL HAVE
THE RIGHT, AT ANY TIME WITHIN TWELVE MONTHS AFTER THE DATE OF DEATH, TO EXERCISE
IN WHOLE OR IN PART ANY RIGHTS THAT WERE AVAILABLE TO THE PARTICIPANT AT THE
TIME OF DEATH. NOTWITHSTANDING THE FOREGOING, NO RIGHTS UNDER THIS STOCK OPTION
MAY BE EXERCISED AFTER THE EXPIRATION DATE.

         8. PAYMENT OF TAXES. THE PARTICIPANT SHALL PAY TO THE COMPANY, OR MAKE
PROVISION SATISFACTORY TO THE COMPANY FOR PAYMENT OF ANY TAXES REQUIRED BY LAW
TO BE WITHHELD WITH RESPECT TO THE EXERCISE OF THIS STOCK OPTION. THE
ADMINISTRATOR MAY, IN ITS DISCRETION, REQUIRE ANY OTHER FEDERAL OR STATE TAXES
IMPOSED ON THE SALE OF THE SHARES TO BE PAID BY THE PARTICIPANT. IN THE
ADMINISTRATOR'S DISCRETION, SUCH TAX OBLIGATIONS MAY BE PAID IN WHOLE OR IN PART
IN SHARES OF STOCK, INCLUDING SHARES RETAINED FROM THE EXERCISE OF THIS STOCK
OPTION, VALUED AT THEIR FAIR MARKET VALUE ON THE DATE OF DELIVERY. THE COMPANY
AND ITS AFFILIATES MAY, TO THE EXTENT PERMITTED BY LAW, DEDUCT ANY SUCH TAX
OBLIGATIONS FROM ANY PAYMENT OF ANY KIND OTHERWISE DUE TO THE PARTICIPANT.

         9. NOTICE OF SALE OF SHARES REQUIRED. THE PARTICIPANT AGREES TO NOTIFY
THE COMPANY IN WRITING WITHIN 30 DAYS OF THE DISPOSITION OF ANY SHARES PURCHASED
UPON EXERCISE OF THIS STOCK OPTION IF SUCH DISPOSITION OCCURS WITHIN TWO YEARS
OF THE DATE OF THE GRANT OF THIS STOCK OPTION OR WITHIN ONE YEAR AFTER SUCH
PURCHASE.

         10. RIGHTS LIMITED. THE ADMINISTRATOR, IN ITS SOLE DISCRETION, SHALL
DETERMINE FROM THE GROUP OF ELIGIBLE PERSONS WHETHER AN INDIVIDUAL SHALL BE A
PARTICIPANT UNDER THE PLAN. ANY GRANT MADE UNDER THE PLAN SHALL BE MADE IN THE
SOLE DISCRETION OF THE ADMINISTRATOR AND NO PRIOR GRANT SHALL ENTITLE A PERSON
TO ANY FUTURE GRANT. NOTHING IN THE PLAN OR ANY STOCK OPTION GRANT WILL BE
CONSTRUED AS GIVING ANY PERSON THE RIGHT TO CONTINUED EMPLOYMENT OR SERVICE WITH
THE COMPANY OR ITS AFFILIATES, OR ANY RIGHTS AS A SHAREHOLDER EXCEPT AS TO
SHARES OF STOCK ACTUALLY ISSUED UNDER THE PLAN. IN NO EVENT SHALL THE PLAN, OR
ANY GRANT MADE UNDER THE PLAN, FORM A PART OF AN EMPLOYEE'S OR CONSULTANT'S
CONTRACT OF EMPLOYMENT OR SERVICE, IF ANY. THE LOSS OF EXISTING OR POTENTIAL
PROFIT IN STOCK OPTIONS WILL NOT CONSTITUTE AN ELEMENT OF DAMAGES IN THE EVENT
OF TERMINATION OF EMPLOYMENT OR SERVICE FOR ANY REASON, EVEN IF THE TERMINATION
IS IN VIOLATION OF AN OBLIGATION OF THE COMPANY OR AFFILIATE TO THE PARTICIPANT.


ACKNOWLEDGED AND AGREED:


------------------------------------
Participant Signature


------------------------------------
Participant Name (Print)


------------------------------------
Date



--------------
(1) The exercisability of options held by Henri A. Termeer and Peter Wirth upon
a change in control of the Company is governed by the terms of their respective
Employment Agreements. This sentence therefore is not included in the form of
Terms and Conditions for stock option grants to Mr. Termeer and Mr. Wirth.