SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF 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* Atlas Venture Opportunity Fund II, L.P. (Last) (First) (Middle) 300 TECHNOLOGY SQUARE, 8TH FLOOR (Street) CAMBRIDGE MA 02139 (City) (State) (Zip)	2. Date of Event Requiring Statement (Month/Day/Year) 12/29/2022	3. Issuer Name and Ticker or Trading Symbol Disc Medicine, Inc. [ IRON ]
		4. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)	5. If Amendment, Date of 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

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock	218,326	D(1)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

1. Name and Address of Reporting Person* Atlas Venture Opportunity Fund II, L.P. (Last) (First) (Middle) 300 TECHNOLOGY SQUARE, 8TH FLOOR (Street) CAMBRIDGE MA 02139 (City) (State) (Zip)

1. Name and Address of Reporting Person* Atlas Venture Associates Opportunity II, LP (Last) (First) (Middle) 300 TECHNOLOGY SQUARE, 8TH FLOOR (Street) CAMBRIDGE MA 02139 (City) (State) (Zip)

1. Name and Address of Reporting Person* Atlas Venture Associates Opportunity II, LLC (Last) (First) (Middle) 300 TECHNOLOGY SQUARE, 8TH FLOOR (Street) CAMBRIDGE MA 02139 (City) (State) (Zip)

Explanation of Responses:

1. These shares are held directly by Atlas Venture Opportunity Fund II, L.P. ("Atlas Opportunity II"). Atlas Venture Associates Opportunity II, L.P. ("Associates II") is the general partner of Atlas Opportunity II. Atlas Venture Associates Opportunity II, LLC ("Associates II LLC") is the general partner of Associates II. Each of Associates II and Associates II LLC disclaims Section 16 beneficial ownership of the securities held by Atlas Opportunity II, except to the extent of its pecuniary interest therein, if any.

Remarks:

	Atlas Venture Opportunity Fund II, L.P., By: Atlas Venture Associates Opportunity II, L.P., its general partner, By: Atlas Venture Associates Opportunity II, LLC, its general partner, By: Ommer Chohan, Chief Financial Officer /s/ Ommer Chohan	01/03/2023
	Atlas Venture Associates Opportunity II, L.P., By: Atlas Venture Associates Opportunity II, LLC, its general partner, By: Ommer Chohan, Chief Financial Officer /s/ Ommer Chohan	01/03/2023
	Atlas Venture Associates Opportunity II, LLC By: Ommer Chohan, Chief Financial Officer /s/ Ommer Chohan	01/03/2023
	** Signature of Reporting Person	Date
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 5 (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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