Sec Form 3 Filing - Casdin Capital, LLC @ GeneDx Holdings Corp. - 2023-01-31

FORM 3 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Casdin Capital, LLC 2. Issuer Name and Ticker or Trading Symbol GeneDx Holdings Corp. [ WGS] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 1350 AVENUE OF THE AMERICAS, SUITE 2600 3. Date of Earliest Transaction (MM/DD/YY) 01/31/2023 (Street) NEW YORK, NY10019 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Class A Common Stock 87,866,042 I See Footnote ( 1 ) Class A Common Stock 14,285,743 I See Footnote ( 2 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Casdin Capital, LLC 1350 AVENUE OF THE AMERICAS SUITE 2600 NEW YORK, NY10019 X X Casdin Partners GP, LLC 1350 AVENUE OF THE AMERICAS SUITE 2600 NEW YORK, NY10019 X X Casdin Partners Master Fund, L.P. 1350 AVENUE OF THE AMERICAS SUITE 2600 NEW YORK, NY10019 X X Casdin Partners FO1-MSV, LP 1350 AVENUE OF THE AMERICAS SUITE 2600 NEW YORK, NY10019 X X Signatures CASDIN CAPITAL, LLC, Name: /s/ Eli Casdin, Title: Managing Member 02/10/2023 Signature of Reporting Person Date CASDIN PARTNERS GP, LLC, Name: /s/ Eli Casdin, Title: Managing Member 02/10/2023 Signature of Reporting Person Date CASDIN PARTNERS MASTER FUND, LP, By: Casdin Partners GP, LLC, Its: General Partner, Name: /s/ Eli Casdin, Title: Managing Member 02/10/2023 Signature of Reporting Person Date CASDIN PARTNERS FO1-MSV, LP, By: Casdin Partners GP, LLC, Its: General Partner, Name: /s/ Eli Casdin, Title: Managing Member 02/10/2023 Signature of Reporting Person Date

Explanation of Responses:

( 1 )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. ( 2 )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.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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