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                                                                   EXHIBIT 10.13
[AMICUS THERAPEUTICS LOGO]


                                LETTER AGREEMENT

                                        March 6, 2006

David Palling, Ph.D.
120 Summit Avenue
Upper Montclair, New Jersey 07043

      Re: CHANGE IN CONTROL AGREEMENT

Dear David:

On behalf of Amicus Therapeutics, Inc., (the "Company"), this shall serve to
confirm our agreement in the event of a Change in Control, Sale or Merger of the
Company. By accepting the terms of this Letter Agreement, you agree that the
rights identified in this Letter Agreement contain the complete understanding
between you and the Company related to Change in Control payments. The July 18,
2002 Offer of Employment Letter countersigned by you ("July 18, 2002 Offer
Letter," attached hereto), shall otherwise remain in full force and effect and
is hereby confirmed and ratified.

CHANGE IN CONTROL

If there is a Change in Control Event and you resign for Good Reason or are
terminated without Cause within six months of such Change in Control Event, then
(i) you will be eligible to receive a continuation of twelve (12) months salary,
plus payment of a bonus payment equal to the bonus earned in the preceding year
and (ii) all unvested stock options will have their remaining vesting schedule
accelerated so that all stock options are fully vested.

"Change in Control Event" means any of the following: (i) any person or entity
(except for a current stockholder) becomes the beneficial owner of greater than
50% of the then outstanding voting power of the company, (ii) a merger or
consolidation with another entity where the voting securities of the company
outstanding immediately before the

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6 Cedar Brook Drive    Cranbury, NJ 08512   T: 609-662-2000   F: 609-662-2001   www.amicustherapeutics.com
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transaction constitute less than a majority of the voting power of the voting
securities of the company or the surviving entity outstanding immediately after
the transaction or (iii) the sale or disposition of all or substantially all of
the company's assets. "Good Reason" means (a) a change in your position with the
company or its successors that materially reduces your title, duties or level of
responsibility; or (b) the relocation of the company or its successor greater
than 50 miles away from the then current location of the company's principal
officers.

Your right to receive accelerated vesting and salary continuation payments
pursuant to the preceding two paragraphs will be subject to and contingent upon
your signing a waiver of rights releasing the Company from any and all further
liability or responsibility.

EMPLOYMENT "AT-WILL"

It is important that you understand that the Company does not guarantee
employment for any specific period of time. You will continue to be employed on
at "at-will" basis. This means that both the Company and you will have the right
to terminate your employment at any time, for any reason, with or without prior
notice or cause. Neither you nor the Company will have an express or implied
contract limiting your right to resign or the Company's right to terminate your
employment at any time, for any reason, with or without prior notice or cause.
The "at-will" relationship will apply to you throughout your employment and
cannot be changed except by an express individual written employment agreement
signed by you and the Chief Executive Officer of the Company.

It is understood and agreed that this Letter Agreement constitutes the full
agreement between you and the Company on the subject of Change in Control
payments. To indicate your acceptance of the terms and conditions set forth
herein, please sign one copy of this Letter Agreement in the space indicated
below and return it to my attention on or before March 13, 2006. By signing
below, you agree that no other promises, express or implied, have been made to
you either verbally or in writing and that no further modifications to these
terms and conditions will be effective except by a written agreement signed by
the Chief Executive Officer of the Company and you and as authorized by the
Company's Board of Directors.

                                        Very truly yours,

                                        /s/ John F. Crowley
                                        -----------------------------------
                                        John F. Crowley
                                        Chairman and Chief Executive Officer

ACCEPTED AND AGREED:

By: /s/ David Palling                   Date: March 9, 2006
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    David Palling, Ph.D.