| Name | Ownership | Shares Owned | sole voting power | shared voting power | Signature | Title | CIK |
|---|---|---|---|---|---|---|---|
| Third Rock Ventures IV, L.P. | 5.85% | 7,874,574 | 0 | 7,874,574 | /s/ Kevin Gillis | Kevin Gillis, COO of TRV GP IV, LLC, the general partner of Third Rock Ventures GP IV, L.P., the general partner of Third Rock Ventures IV, L.P. | 0001688327 |
| Third Rock Ventures GP IV, L.P. | 5.85% | 7,874,574 | 0 | 7,874,574 | /s/ Kevin Gillis | Kevin Gillis, COO of TRV GP IV, LLC, the general partner of Third Rock Ventures GP IV, L.P. | 0001688326 |
| TRV GP IV, LLC | 5.85% | 7,874,574 | 0 | 7,874,574 | /s/ Kevin Gillis | Kevin Gillis, COO | 0001688325 |