<PAGE>   1
                                                                   Exhibit 10.46


                              deCODE GENETICS, INC.

                        FOUNDER STOCK PURCHASE AGREEMENT

THIS AGREEMENT is made as of the 21st day of August, 1996 by and between deCODE
GENETICS, INC., a Delaware corporation (the "Corporation"), and JEFFREY R.
GULCHER (the "Purchaser").

         WHEREAS, pursuant to Section 152 of the Delaware General Corporation
Law, the Corporation desires to issue, and the Purchaser desires to acquire,
stock of the Corporation as herein described, on the terms and conditions
hereinafter set forth:

         WHEREAS, the issuance of Common Stock hereby is, where applicable, in
connection with a compensatory benefit plan for the employees, directors,
officers, advisers or consultants of the Corporation and is intended to comply
with the provisions of Rule 701 promulgated by the Securities and Exchange
Commission (the "SEC") under the Securities Act of 1933, as amended (the "Act").

         NOW, THEREFORE, IT IS AGREED between the parties as follows:

         1. The Purchaser hereby agrees to purchase from the Corporation, and
the Corporation hereby agrees to sell to the Purchaser, an aggregate of Four
Hundred Eighty One Thousand Two Hundred (481,200) shares of the Common Stock of
the Corporation (the "Stock") at one tenth of one cent ($.001) per share, for an
aggregate purchase price of $481.200, which amount shall be payable in cash.

         2. The shares to be purchased by the Purchaser pursuant to this
Agreement (hereinafter sometimes collectively referred to as the "Stock") shall
be subject to the repurchase options of the Corporation set forth in
subparagraphs (a) and (b) below ("Purchase Option"):


                                       1.
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                  (a) In the event the Purchaser ceases to be an employee of the
Corporation as a result of (1) voluntary or mutual termination of Purchaser's
employment (except as a result of bona fide medical disability); or (2)
termination of Purchaser's employment by the Company for any of the following
reasons: (A) indictment or conviction of any felony or of any crime involving
dishonesty; (B) participation in any fraud against the Company; (C) breach of
Purchaser's duties to the Company, including, without limitation, persistent
unsatisfactory performance of job duties or breach of loyalty (except as a
result of bona fide medical disability); (D) intentional damage to any Company
property; or (E) conduct by Purchaser which in the good faith and reasonable
determination of the Board demonstrates gross unfitness to serve, the
Corporation shall have the right as set forth herein, to exercise its Purchase
Option. The Corporation may, by exercising its Purchase Option at any time
within ninety (90) business days after said cessation or such longer period as
may be determined by the Company if such later repurchase is deemed necessary by
the Company for treatment of its stock as Qualified Small Business Stock under
Section 1202 of the Internal Revenue Code of 1986, as amended and regulations
promulgated thereunder, repurchase from the Purchaser or his personal
representative, as the case my be, at the total price per share indicated above
as paid by the Purchaser for such Stock ("Option Price"), up to but not
exceeding the number of shares of stock which have not vested under the
provisions of paragraph (b) below. As used herein, employment with the
Corporation shall include employment with a "parent" or "subsidiary" of the
Corporation as those terms are defined in Sections 424(e) and (f) of the
Internal Revenue Code of 1986, as amended.

                  (b) The right of the Corporation to exercise its Purchase
Option as to the maximum portion of the stock specified in the event of
termination shall be by reference to the following schedule.


                                       2.
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                  (i) 10% of the stock issued to the Purchaser shall vest as of
the date of this Agreement; and

                  (ii) 1.875% of the stock issued to the Purchaser shall vest
monthly thereafter.

            (c) The Corporation shall be entitled to pay for any shares
purchased pursuant to it Purchase Option at the Corporation's option in cash or
by offset against any indebtedness owing to the Corporation by Purchaser
(including without limitation any Note given in payment for the Stock).

            (d) Nothing in this Agreement shall affect in any manner whatsoever
the right or power of the Corporation (or a parent or subsidiary of the
Corporation) to terminate Purchaser's employment.

         3. The Purchase Option shall be exercised by written notice signed by
an officer of the Corporation or by any assignee or assignees of the Corporation
and delivered or mailed as provided in paragraph 13. Such notice shall identify
the number of shares to be purchased and shall notify the Purchaser of the time,
place and date for settlement of such purchase, which shall be scheduled by the
Corporation within one hundred fifty (150) business days from the date of
cessation of employment.

         4. If, from time to time during the term of the Purchase Option:

                  (i) There is any stock dividend or other distribution of cash
and/or property, stock split or other change in the character or amount of any
of the outstanding securities of the Corporation; or

                  (ii) There is any consolidation, merger or sale of all, or
substantially all of the assets of the Corporation;


                                       3.
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then, in such event, any and all new, substituted or additional securities or
other property to which the Purchaser is entitled by reason of its ownership of
Stock shall be immediately subject to the Purchase Option and be included in the
word "Stock" for all purposes of the Purchase Option with the same force and
effect as the shares of the Stock presently subject to the Purchase Option.
While the total Option Price shall remain the same after each such event, the
Option Price per share of Stock upon exercise of the Purchase Option shall be
appropriately adjusted.

         Upon the occurrence of any event specified in clause (ii) above, the
Purchase Option may be assigned to any successor to the Corporation, and the
Purchase Option shall apply if the Purchaser does not become or shall cease for
any reason to be employed by such successor (or its parent or subsidiaries). In
such case, the references herein to the "Corporation" shall be deemed to refer
to such successor.

         5. All certificates representing any shares of Stock of the Corporation
subject to the provisions of this Agreement shall have endorsed thereon legends
in substantially the following forms (in addition to any other legend which may
be required by other agreements between the parties hereto):

                  (i) "The shares represented by this certificate are subject to
an option set forth in an agreement between the Corporation and the registered
holder, or his predecessor in interest, a copy of which is on file at the
principal office of the Corporation. Any transfer or attempted transfer of any
shares subject to such option is void without the prior express written consent
of the issuer of these shares."

                  (ii) "The securities represented by this Certificate have not
been registered under the Securities Act of 1933. They may not be sold, offered
for sale, pledged or hypothecated in the absence of an effective registration
statement as to the securities under



                                       4.
<PAGE>   5
said Act or an opinion of counsel satisfactory to the Company that such
registration is not required."

                  (iii) "The shares represented by this certificate are subject
to a right of first refusal option in favor of the corporation and/or its
assignee(s) as provided in the bylaws of the Corporation."

                  (iv) Any legend required by applicable state securities laws.

         6. Purchaser acknowledges that he is aware that the Stock to be issued
to him by the Corporation pursuant to this Agreement has not been registered
under the Act, and that the Stock is deemed to constitute "restricted
securities" under Rule 701 and Rule 144 promulgated under the Act. In this
connection, Purchaser warrants and represents to the Corporation that Purchaser
is purchasing the Stock Purchaser's own account and Purchaser has no present
intention of distributing or selling said stock except as permitted under the
Act and under applicable state securities laws. Purchaser further warrants and
represents that Purchaser has either (i) preexisting personal or business
relationships with the Corporation or any of its officers, directors or
controlling persons, or (ii) the capacity to protect his own interests in
connection with the purchase of the Stock by virtue of the business or financial
expertise of himself or of professional advisors to the Purchaser who are
unaffiliated with and who are not compensated by the Corporation or any of its
affiliates, directly or indirectly. Purchaser further acknowledges that the
exemption from registration under Rule 144 will not be available for at least
three years from the date of sale of the Stock unless at least two years from
the date of sale (i) a public trading market then exists for the Common Stock of
the Corporation, (ii) adequate information concerning the Corporation is then
available to the public, and (iii) other terms and conditions of Rule 144 are
complied with; and that any sale of the Stock may be made only in limited
amounts in accordance with such terms and conditions and that exemption from
registration


                                       5.
<PAGE>   6
under Rule 701 will not be available until ninety days after the Corporation
becomes subject to the reporting requirements of Section 13 or 15(d) of the
Securities Exchange Act of 1934 and that after such date the Stock may be resold
by persons other than affiliates in reliance on Rule 144 without compliance with
paragraphs (c), (d), (e) and (h) thereof, and by affiliates without compliance
with paragraph (d) thereof.

         7. The Purchaser agrees that during the one hundred eighty (180) day
period following the effective date of a registration statement of the
Corporation filed under the Act of the Purchaser shall not, to the extent
requested by the Corporation and any underwriter, sell or otherwise transfer or
dispose of (other than to donees who agree to be similarly bound), or enter into
any hedging or similar transaction with the same economic effect as a sale, any
Common Stock of the Corporation held by the Purchaser at any time during such
period (the "Purchaser's Registrable Securities") except Common Stock included
in such registration; provided, however, that:

                  (a) such agreement shall be applicable only to the first such
registration statement of the Corporation which covers Common Stock (or other
securities) to be sold on its behalf to the public in an underwritten offering;
and

                  (b) all officers and directors of the Corporation enter into
similar agreements. In order to enforce the foregoing covenant, the Corporation
may impose stop-transfer instructions with respect to the Purchaser's
Registrable Securities (and the shares or securities of every other person
subject to the foregoing restriction) until the end of such period.

         8. The Purchaser shall not transfer by sale, assignment, hypothecation,
donation or otherwise any of the Stock or any interest therein subject to the
Purchase Option without the prior express written consent of the issuer of the
shares. As security for his faithful performance of the terms of this Agreement
and to insure the availability for delivery of Purchaser's Stock



                                       6.
<PAGE>   7
upon exercise of the Purchase Option herein provided for, the Purchaser agrees,
at the closing hereunder, to deliver to and deposit with the Secretary of the
Corporation ("Escrow Agent"), as Escrow Agent in this transaction, three stock
assignments duly endorsed (with date and number of shares blank) in the form
attached hereto as Exhibit B, together with a certificate or certificates
evidencing all of the Stock subject to the Purchase Option; said documents are
to be held by the Escrow Agent and delivered by said Escrow Agent pursuant to
the Joint Escrow Instructions of the Corporation and the Purchaser set forth in
Exhibit A attached hereto and incorporated by this reference, which instructions
shall also be delivered to the Escrow Agent at the closing hereunder.

         9. The Corporation shall not be required (i) to transfer on its books
any shares of Stock of the Corporation which shall have been transferred in
violation of any of the provisions set forth in this Agreement or (ii) to treat
as owner of such shares or to accord the right to vote as such owner or to pay
dividends to any transferee to whom such shares shall have been so transferred.

         10. Subject to provisions of paragraphs 7, 8, and 9 above, the
Purchaser (but not any unapproved transferee) shall exercise all rights and
privileges of a shareholder of the Corporation with respect to the Stock.

         11. Paragraphs 2, 3 and 4 of this Agreement shall terminate upon the
exercise in full or expiration of the Purchase Option, whichever first occurs.

         12. The parties agree to execute such further instruments and to take
such further action as may reasonably be necessary to carry out the intent of
this Agreement.

         13. Any notice required or permitted hereunder shall be given in
writing and shall be deemed effectively given upon personal delivery or upon
deposit in the United States Post Office, by registered or certified mail with
postage and fees prepaid, addressed to the other party


                                       7.
<PAGE>   8
hereto at his address hereinafter shown below its signature or at such other
address as such party may designate by ten (10) days advance written notice to
the other party hereto.

         14. This Agreement shall inure to the benefit of the successors and
assigns of the Corporation and, subject to the restrictions on transfer herein
set forth, be binding upon the Purchaser, its successors, and assigns. The
Purchase Option of the Corporation hereunder shall be assignable by the
Corporation at any time or from time to time, in whole or in part.

         15. The Purchaser shall reimburse the Corporation for all costs
incurred by the Corporation in enforcing the performance of, or protecting its
rights under, any part of this Agreement, including reasonable costs of
investigation and attorney's fees. It is the intention of the parties that the
Corporation, upon exercise of the Purchase Option and payment of the Option
Price, pursuant to the terms of this Agreement, shall be entitled to receive the
Stock, in specie, in order to have such Stock available for future issuance
without dilution of the holdings of other shareholders. Furthermore, it is
expressly agreed between the parties that money damages are inadequate to
compensate the Corporation for the Stock and that the Corporation shall, upon
proper exercise of the Purchase Option, be entitled to specific enforcement of
its rights to purchase and receive said Stock.

         16. This Agreement shall be governed by and construed in accordance
with the laws of the State of Delaware. The parties agree that any action
brought by either party to interpret or enforce any provision of this Agreement
shall be brought in, and each party agrees to, and does hereby, submit to the
jurisdiction and venue of, the appropriate state or federal court for the
district encompassing the Corporation's principal place of business.

         17. The parties agree to take all such further action(s) as may
reasonably be necessary to carry out and consummate this Agreement as soon as
practicable, and to take whatever steps may be necessary to obtain any
governmental approval in connection with or otherwise qualify



                                       8.
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the issuance of the securities that are the subject of this Agreement. The
closing hereunder, including payment for and delivery of the Stock, shall occur
at the offices of Cooley Godward Castro Huddleson & Tatum in Palo Alto,
California on the date hereof, or at such other time and place as the parties
may mutually agree.

         18. This Agreement is not an employment contract and nothing in this
Agreement shall be deemed to create in any way whatsoever any obligations on the
part of the Purchaser to continue in the employ of the Corporation or of the
Corporation to continue the Purchaser in the employ of the Corporation.

         19. Purchaser acknowledges that this Agreement has been prepared on
behalf of the Company by Cooley Godward Castro Huddleson & Tatum, counsel to the
Company and that Cooley Godward does not represent, and is not acting on behalf
of, Purchaser. Purchaser has been provided with an opportunity to consult with
its own counsel with respect to this Agreement.

         20. This Agreement constitutes the entire agreement between the parties
with respect to the subject matter hereof. This Agreement may not be amended,
modified or revoked, in whole or in part, except by an agreement in writing
signed by each of the parties hereto.



                                       9.
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         IN WITNESS WHEREOF, the parties hereto have executed this Agreement as
of the day and year first above written.

                                     deCODE GENETICS, INC.

                                     --------------------------------------
                                     By:      /s/ Kari Stefansson
                                              ------------------------------
                                     Title:   President and CEO
                                              ------------------------------
                                     Address:       Lynghals 1 Reykjavik
                                              ------------------------------
                                                    Iceland
                                              ------------------------------

                                     PURCHASER:

                                     By:      /s/ Jeffrey Gulcher
                                              ------------------------------

                                     Name:    Jeffrey R. Gulcher

                                     Address:       140 Sumner Rd.
                                              ------------------------------
                                                    Brookline, MA 02215
                                              ------------------------------

ATTACHMENTS:

Exhibit A         --       Joint Escrow Instructions
Exhibit B         --       Stock Assignment Separate from Certificate



                                      10.
<PAGE>   11
                                    EXHIBIT A

                            JOINT ESCROW INSTRUCTIONS

Alan C.  Mendelson, Esq.
Counsel to deCODE genetics, Inc.
c/o Cooley Godward Castro Huddleson & Tatum
Five Palo Alto Square
3000 El Camino Real
Palo Alto, CA  94306

Dear Sir:

         As Escrow Agent for both deCODE genetics, Inc., a Delaware corporation
("Corporation"), and Jeffrey R. Gulcher ("Purchaser"), you are hereby authorized
and directed to hold the documents delivered to you pursuant to the terms of
that certain Stock Purchase Agreement ("Agreement") dated as of August 21, 1996,
to which a copy of these Joint Escrow Instructions is attached as EXHIBIT A, in
accordance with the following instructions:

         1. In the event Corporation or an assignee shall elect to exercise the
Purchase Option set forth in the Agreement, the Corporation or its assignee will
give to Purchaser and you a written notice specifying the number of shares of
stock to be purchased, the purchase price, and the time for a closing thereunder
at the principal office of the Corporation. Purchaser and the Corporation hereby
irrevocably authorize and direct you to close the transaction contemplated by
such notice in accordance with the terms of said notice.

         2. At the closing, you are directed (a) to date the stock assignments
necessary for the transfer in question, (b) to fill in the number of shares
being transferred, and (c) to deliver the same, together with the certificate
evidencing the shares of stock to be transferred, to the Corporation against the
simultaneous delivery to you of the purchase price (which may include suitable
acknowledgment of cancellation of indebtedness) for the number of shares of
stock being purchased pursuant to the exercise of the Purchase Option.

         3. Purchaser irrevocably authorizes the Corporation to deposit with any
certificates evidencing shares of stock to be held by you hereunder and any
additions and substitutions to said shares as specified in the Agreement.
Purchaser does hereby irrevocably constitute and appoint you as his
attorney-in-fact and agent for the term of this escrow to execute with respect
to such securities all documents necessary or appropriate to make such
securities negotiable and complete any transaction herein contemplated,
including but not limited to any appropriate filing with state or government
officials or bank officials. Subject to the provisions of this paragraph 3,
Purchaser shall exercise all rights and privileges of a shareholder of the
Corporation while the stock is held by you.


                                       1.
<PAGE>   12
         4. This escrow shall terminate upon the exercise in full or expiration
of the Purchase Option, whichever occurs first.

         5. If at the time of termination of this escrow you should have in your
possession any documents, securities, or other property belonging to Purchaser,
you shall deliver all of the same to Purchaser and shall be discharged of all
further obligations hereunder; provided, however, that if at the time of
termination of this escrow you are advised by the Corporation that any property
subject to this escrow is the subject of a pledge or other security agreement,
you shall deliver all such property to the pledgeholder or other person
designated by the Corporation.

         6. Your duties hereunder may be altered, amended, modified or revoked
only by a writing signed by all of the parties hereto.

         7. You shall be obligated only for the performance of such duties as
are specifically set forth herein and may rely and shall be protected in relying
or refraining from acting on any instrument reasonable believed by you to be
genuine and to have been signed or presented by the proper party or parties. You
shall not be personally liable for any act you may do or omit to do hereunder as
Escrow Agent or as attorney-in-fact for Purchaser while acting in good faith and
in the exercise of your own good judgment, and any act done or omitted by you
pursuant to the advice of your own attorneys shall be conclusive evidence of
such good faith.

         8. You are hereby expressly authorized to disregard any and all
warnings given by any of the parties hereto or by any other person or
corporation, excepting only orders or process of courts of law, and are hereby
expressly authorized to comply with and obey orders, judgments or decrees of any
court. In case you obey or comply with any such order, judgment or decree of any
court, you shall not be liable to any of the parties hereto or to any other
person, firm or corporation by reason of such compliance, notwithstanding any
such order, judgment or decree being subsequently reversed, modified, annulled,
set aside, vacated or found to have been entered without jurisdiction.

         9. You shall not be liable in any respect on account of the identify,
authorities or rights of the parties executing or delivering or purporting to
execute or deliver the Agreement or any documents or papers deposited or called
for hereunder.

         10. You shall not be liable for the outlawing of any rights under any
statute of limitations with respect to these Joint Escrow Instructions or any
documents deposited with you.

         11. Your responsibilities as Escrow Agent hereunder shall terminate if
you shall cease to be Counsel to the Corporation or if you shall resign by
written notice to each party. In the event of any such termination, the
Corporation shall appoint any officer or assistant officer of the Corporation as
successor Escrow Agent, and Purchaser hereby confirms the appointment of such
successor as his attorney-in-fact and agent to the full extent of your
appointment.


                                       2.
<PAGE>   13
         12. If you reasonably require other or further instruments in
connection with these Joint Escrow Instructions or obligations in respect
hereto, the necessary parties hereto shall join in furnishing such instruments.

         13. It is understood and agreed that should any dispute arise with
respect to the delivery and/or ownership or right of possession of the
securities held by you hereunder, you are authorized and directed to retain in
your possession without liability to anyone all or any part of said securities
until such dispute shall have been settled either by mutual written agreement of
the parties concerned or by a final order, decree or judgment of a court of
competent jurisdiction after the time for appeal has expired and no appeal has
been perfected, but you shall be under no duty whatsoever to institute or defend
any such proceedings.

         14. Any notice required or permitted hereunder shall be given in
writing and shall be deemed effectively given upon personal delivery, including
delivery by express courier, or four (4) days after deposit in the United States
Post Office, by registered or certified mail with postage and fees prepaid,
addressed to each of the other parties entitled to such notice at the following
addresses, or at such other addresses as a party may designate by ten days'
advance written notice to each of the other parties hereto.

         CORPORATION:      deCODE genetics, Inc.
                           Attention:  Kari Stefansson
                           Lynghals 1
                           Reykjavik 110
                           Iceland

         PURCHASER:        Jeffrey R. Gulcher
                           140 Sumner Road
                           Brookline, MA 02115

         ESCROW AGENT:     Alan C. Mendelson, Esq.
                           Cooley Godward Castro Huddleson & Tatum
                           Five Palo Alto Square
                           3000 El Camino Real
                           Palo Alto, CA 94306

         15. By signing these Joint Escrow Instructions, you become a party
hereto only for the purpose of said Joint Escrow Instructions; you do not become
a party to the Agreement.

         16. You shall be entitled to employ such legal counsel and other
experts (including, without limitation, the firm of Cooley Godward Castro
Huddleson Tatum) as you may deem necessary properly to advise you in connection
with your obligations hereunder. You may rely upon the advice of such counsel,
and you may pay such counsel reasonable compensation.


                                       3.
<PAGE>   14
         17. This instrument shall be binding upon and inure to the benefit of
the parties hereto and their respective successors and permitted assigns.

         18. This Agreement shall be governed by and interpreted and determined
in accordance with the laws of the State of Delaware as such laws are applied by
Delaware courts to contracts made and to be performed entirely in Delaware by
residents of that state.

                                       Very truly yours,

                                                deCODE genetics, Inc.

                                                /s/ Kari Stefansson
                                                -------------------------------
                                                Kari Stefansson
                                                President

                                                PURCHASER:

                                                Signature:  /s/ Jeff Gulcher
                                                            -------------------
                                                Name:       Jeff Gulcher
                                                            -------------------


ESCROW AGENT:

/s/ Alan C. Mendelson
-------------------------
Alan C. Mendelson, Esq.



                                       4.
<PAGE>   15
                                    EXHIBIT B

                   STOCK ASSIGNMENT SEPARATE FROM CERTIFICATE

         FOR VALUE RECEIVED,        hereby sells, assigns, and transfers unto
deCODE genetics, Inc. a Delaware corporation (the "Company"), pursuant to the
Purchase Option under that certain Stock Purchase Agreement, dated August   ,
1996, by and between the undersigned and the Company (the "Agreement"),
shares of Common Stock of the Company standing the undersigned's name on the
books of the Company represented by Certificate No.      and does hereby
irrevocably constitute and appoint the Company's Secretary attorney to transfer
said stock on the books of the Company with full power of substitution in the
premises. This Assignment may be used only in accordance with and subject to the
terms and conditions of the Agreement, in connection with the repurchase of
shares of Common Stock issued to the undersigned pursuant to the Agreement, and
only to the extent that such shares remain subject to the Company's Purchase
Option under the Agreement.

Dated:   8-16-96
         ------------------------

                                                       /s/ Jeff Gulcher
                                                       ------------------------
                                                       (Signature)

                                                       Jeff Gulcher
                                                       ------------------------
                                                       (Name)

                                       5.