X0206 3 2023-01-31 0 0001818331 GeneDx Holdings Corp. WGS 0001534261 Casdin Capital, LLC 1350 AVENUE OF THE AMERICAS SUITE 2600 NEW YORK NY 10019 1 0 1 0 0001534260 Casdin Partners GP, LLC 1350 AVENUE OF THE AMERICAS SUITE 2600 NEW YORK NY 10019 1 0 1 0 0001534265 Casdin Partners Master Fund, L.P. 1350 AVENUE OF THE AMERICAS SUITE 2600 NEW YORK NY 10019 1 0 1 0 0001938709 Casdin Partners FO1-MSV, LP 1350 AVENUE OF THE AMERICAS SUITE 2600 NEW YORK NY 10019 1 0 1 0 Class A Common Stock 87866042 I See Footnote Class A Common Stock 14285743 I See Footnote The 87,866,042 shares of Class A common stock reported in the table above are owned directly by Casdin Partners Master Fund, LP and may be deemed to be indirectly beneficially owned by (i) Casdin Capital, LLC, the investment adviser to Casdin Partners Master Fund, LP, (ii) Casdin Partners GP, LLC, the general partner of Casdin Partners Master Fund LP, and (iii) Mr. Casdin, the managing member of Casdin Capital, LLC and Casdin Partners GP, LLC. Each of Casdin Capital, LLC, Casdin Partners GP, LLC and Mr. Casdin disclaims beneficial ownership of such securities except to the extent of its or his respective pecuniary interest therein. The 14,285,743 shares of Class A common stock reported in the table above are owned directly by Casdin Partners FO1-MSV, LP and may be deemed to be indirectly beneficially owned by (i) Casdin Capital, LLC, the investment adviser to Casdin Partners FO1-MSV, LP, (ii) Casdin Partners GP, LLC, the general partner of Casdin Partners FO1-MSV, LP, and (iii) Mr. Casdin, the managing member of Casdin Capital, LLC and Casdin Partners GP, LLC. Each of Casdin Capital, LLC, Casdin Partners GP, LLC and Mr. Casdin disclaims beneficial ownership of such securities except to the extent of its or his respective pecuniary interest therein. CASDIN CAPITAL, LLC, Name: /s/ Eli Casdin, Title: Managing Member 2023-02-10 CASDIN PARTNERS GP, LLC, Name: /s/ Eli Casdin, Title: Managing Member 2023-02-10 CASDIN PARTNERS MASTER FUND, LP, By: Casdin Partners GP, LLC, Its: General Partner, Name: /s/ Eli Casdin, Title: Managing Member 2023-02-10 CASDIN PARTNERS FO1-MSV, LP, By: Casdin Partners GP, LLC, Its: General Partner, Name: /s/ Eli Casdin, Title: Managing Member 2023-02-10