Statement of Changes in Beneficial Ownership (Form 4)

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b). Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 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 (Month/Day/Year) 05/07/2026 (Street) NEW YORK, NY 10019 4. If Amendment, Date Original Filed (Month/Day/Year) 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 (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 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

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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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 (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

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 (Month/Day/Year)

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

Cash Settled Swap

(1)

05/07/2026

P/K

500,000

(1)

(1)

Class A Common Stock

500,000

(1)

500,000

I

See Footnote(2)

Cash Settled Swap

(3)

05/08/2026

P/K

300,000

(3)

(3)

Class A Common Stock

300,000

(3)

800,000

I

See Footnote(2)

Cash Settled Swap

(4)

05/11/2026

P/K

50,000

(4)

(4)

Class A Common Stock

50,000

(4)

850,000

I

See Footnote(2)

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Casdin Capital, LLC 1350 AVENUE OF THE AMERICAS SUITE 2600 NEW YORK, NY 10019	X	X
Casdin Eli 1350 AVENUE OF THE AMERICAS SUITE 2600 NEW YORK, NY 10019	X	X
Casdin Partners Master Fund, L.P. 1350 AVENUE OF THE AMERICAS SUITE 2600 NEW YORK, NY 10019	X	X
Casdin Partners GP, LLC 1350 AVENUE OF THE AMERICAS SUITE 2600 NEW YORK, NY 10019	X	X

Signatures

Casdin Capital LLC, By: /s/ Eli Casdin, Managing Member		05/11/2026
**Signature of Reporting Person		Date
/s/ Eli Casdin, Eli Casdin		05/11/2026
**Signature of Reporting Person		Date
Casdin Partners Master Fund, LP, By: Casdin Partners GP, LLC, its General Partner, By: /s/ Eli Casdin, Managing Member		05/11/2026
**Signature of Reporting Person		Date
Casdin Partners GP LLC, By: /s/ Eli Casdin, Managing Member, /s/ Eli Casdin, Eli Casdin		05/11/2026
**Signature of Reporting Person		Date

Explanation of Responses:

*	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).
(1)	Casdin Partners Master Fund, L.P. (the "Master Fund") has entered into certain cash-settled swap agreements (the "Swap Agreements"), which represent economic exposure to an aggregate of 500,000 notional shares of the Issuer's Class A Common Stock, at a price of $38.1543 per share. The Swap Agreements provide the Master Fund with economic results that are comparable to the economic results of ownership but do not provide it with the power to vote or direct the voting or dispose of or direct the disposition of the securities that are referenced by the Swap Agreements.
(2)	The Swap Agreements are owned directly by the Master Fund and may be deemed to be indirectly beneficially owned by (i) Casdin Capital, LLC, the investment adviser to the Master Fund ("Casdin"), (ii) Casdin Partners GP, LLC, the general partner of the Master Fund (the "GP"), and (iii) Eli Casdin, the managing member of Casdin and the GP.
(3)	The Master Fund has entered into certain cash-settled swap agreements (the "Swap Agreements"), which represent economic exposure to an aggregate of 300,000 notional shares of the Issuer's Class A Common Stock, at a price of $41.0261 per share. The Swap Agreements provide the Master Fund with economic results that are comparable to the economic results of ownership but do not provide it with the power to vote or direct the voting or dispose of or direct the disposition of the securities that are referenced by the Swap Agreements.
(4)	The Master Fund has entered into certain cash-settled swap agreements (the "Swap Agreements"), which represent economic exposure to an aggregate of 50,000 notional shares of the Issuer's Class A Common Stock, at a price of $39.6602 per share. The Swap Agreements provide the Master Fund with economic results that are comparable to the economic results of ownership but do not provide it with the power to vote or direct the voting or dispose of or direct the disposition of the securities that are referenced by the Swap Agreements.
Remarks: Each Reporting Person disclaims beneficial ownership in the securities reported on this Form 4 except to the extent of its pecuniary interest, if any, therein, and this report shall not be deemed to be an admission that such Reporting Person is the beneficial owner of such securities for purposes of Section 16 or for any other purpose.

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