QuickLinks -- Click here to rapidly navigate through this document

EXHIBIT 21

List of Subsidiaries of the Registrant

1.	Callidus Biopharma, Inc. (Delaware)
2.	Scioderm, Inc. (Delaware)
3.	Scioderm Limited (Ireland)
4.	MiaMed, Inc. (Delaware)
5.	Amicus Therapeutics International Holding Limited (UK)
6.	Amicus Therapeutics UK Limited (UK)
7.	Amicus Therapeutics SAS (France)
8.	Amicus Therapeutics B.V. (Netherlands)
9.	Amicus Therapeutics GmbH (Germany)
10.	Amicus Therapeutics S.L.U. (Spain)
11.	Amicus Therapeutics S.r.l. (Italy)
12.	Amicus Therapeutics K.K. (Japan)
13.	Amicus Therapeutics Canada Inc. (Canada)
14.	Amicus Therapeutics PTY LTD (Australia)
15.	Amicus Therapeutics US, Inc. (Delaware)

QuickLinks

EXHIBIT 21

List of Subsidiaries of the Registrant