**EXHIBIT 21**

**SUBSIDIARIESOF THE REGISTRANT**

| Name                                              | ** ** | ** **                                             | ** ** | **Direct Parent(s)** | ** ** | **Ownership** | ** **           | **Jurisdiction of  Incorporation** |
|---------------------------------------------------|------------|--------------------------------------------------------|------------|----------------------|------------|---------------|----------------------|------------------------------------|
| BioMarin/Genzyme LLC                              |       | Genzyme  Corporation                                   |       | 50%                  |       |          | Delaware             |
| Genzyme Europe B.V.                               |       | Imtix SangStat  (Switzerland) GmbH                     |       | 100%                 |       |          | The Netherlands      |
| Genzyme Flanders BVBA                             |       | Genzyme  International Holdings Limited                |       | 99.9%                |       |          | Belgium              |
|                                              |       | SangStat Luxembourg S.à.r.l.                      |       | 0.1%                 |       |          |                 |
| Genzyme GmbH                                      |       | Genzyme Europe  B.V.                                   |       | 100%                 |       |          | Germany              |
| Genzyme International  Holdings Limited           |       | SangStat  Luxembourg S.à.r.l.                     |       | 100%                 |       |          | Ireland              |
| Genzyme Ireland Limited                           |       | Genzyme  International Holdings Limited                |       | 100%                 |       |          | Republic of  Ireland |
| Genzyme Limited                                   |       | Genzyme  Corporation                                   |       | 100%                 |       |          | United Kingdom       |
| Genzyme Securities  Corporation                   |       | Genzyme  Corporation                                   |       | 100%                 |       |          | Massachusetts        |
| Genzyme Pharmaceuticals  AG                       |       | SangStat  Luxembourg S.à.r.l.                     |       | 100%                 |       |          | Switzerland          |
| Genzyme Polyclonals  S.A.S.                       |       | SangStat Medical,  LLC SangStat Atlantique S.A.S. |       | 1%

99%              |       |          | France               |
| Genzyme Therapeutic  Products Limited Partnership |       | Genzyme Therapeutic                                    |       | 1%                   |       |          | Massachusetts        |
|                                              |       | Products  Corporation                                  |       |                 |       |          |                 |
|                                              |       | Genzyme  Therapeutic  Products LLC                     |       | 99%                  |       |          |                 |
| Genzyme Therapeutic  Products Corporation         |       | Genzyme  Corporation                                   |       | 100%                 |       |          | Massachusetts        |
| Genzyme Therapeutic  Products LLC                 |       | Genzyme  Corporation                                   |       | 100%                 |       |          | Delaware             |
| Imtix SangStat  (Switzerland) GmbH                |       | SangStat  Luxembourg S.à.r.l.                     |       | 100%                 |       |          | Switzerland          |
| SangStat Atlantique  S.A.S.                       |       | SangStat Medical,  LLC                                 |       | 100%                 |       |          | France               |
| SangStat Luxembourg S.à.r.l.                 |       | Genzyme Luxembourg  S.à.r.l.                      |       | 100%                 |       |          | Luxembourg           |

 

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