Disc Medicine, Inc.

NOTICE OF 2026 ANNUAL MEETING OF STOCKHOLDERS

To be held June 18, 2026

Dear Stockholder,

Notice is hereby given that the 2026 Annual Meeting of Stockholders, or Annual Meeting, of Disc Medicine, Inc., will be held on June 18, 2026 at 9:00 A.M. Eastern Time. The Annual Meeting will be a completely virtual meeting, which will be conducted by live webcast at www.virtualshareholdermeeting.com/IRON2026. You will be able to vote electronically and submit questions during the virtual meeting. You will need the 16 digit control number, which is located on the Notice of Internet Availability of Proxy Materials, or the Notice, that you received in the mail, on your proxy card, or in the instructions accompanying your proxy materials, to attend the virtual meeting. The purpose of the Annual Meeting is the following:

To elect three Class III directors to our board of directors, to serve until the 2029 annual meeting of stockholders and until their successors have been duly elected and qualified, or until their earlier death, resignation or removal;

To approve, on a non-binding, advisory basis, the compensation paid to our named executive officers;

To ratify the appointment of Ernst & Young LLP as our independent registered public accounting firm for the fiscal year ending December 31, 2026; and

To transact any other business properly brought before the Annual Meeting or any adjournment or postponement of the Annual Meeting.

The proposal for the election of directors relates solely to the election of three Class III directors nominated by the board of directors.

Only Disc Medicine, Inc. stockholders of record at the close of business on April 22, 2026 will be entitled to vote at the Annual Meeting and any adjournment or postponement thereof.

You can find more information on each of the matters to be voted on at the Annual Meeting, including information regarding the nominees for election to our board of directors, in the accompanying Proxy Statement. Our board of directors recommends a vote “FOR” the election of the three nominees for Class III directors, “FOR” the approval, on a non-binding, advisory basis, of the compensation paid to our named executive officers, and “FOR” the ratification of the appointment of the Company’s independent registered public accounting firm for the fiscal year ending December 31, 2026.

Disc Medicine, Inc. is following the Securities and Exchange Commission’s “Notice and Access” rule that allows companies to furnish their proxy materials by posting them on the Internet. As a result, we are mailing to our stockholders a Notice of Internet Availability of Proxy Materials, or the Notice, instead of a paper copy of the accompanying proxy statement and our Annual Report on Form 10-K for the fiscal year ended December 31, 2025, or 2025 Annual Report. The Notice contains instructions on how to access both the 2025 Annual Report and accompanying proxy statement over the Internet. This method provides our stockholders with expedited access to proxy materials, lowers the cost of printing and distribution, and reduces the environmental impact of the Annual Meeting. If you would like to receive a print version of the proxy materials, free of charge, please follow the instructions on the Notice.

Please see the “General Information” section of the proxy statement that accompanies this notice for more details regarding the logistics of the Annual Meeting.

Your vote is important. Whether or not you expect to attend the virtual meeting, it is important that your shares be represented. To ensure that your vote is recorded promptly, please vote as soon as possible, even if you plan to attend the virtual meeting, by submitting your proxy via the Internet at the address listed on the proxy card or by signing, dating and returning the proxy card. Even if you have voted by proxy, you may still vote online during the virtual meeting. Please note, however, that if your shares are held through a broker, bank or other nominee and you wish to vote at the virtual meeting, you must obtain a proxy issued in your name from that record holder.

/s/ John Quisel, J.D., Ph.D.

John Quisel, J.D., Ph.D.

President and Chief Executive Officer

Watertown, MA

April 28, 2026

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