UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

(Amendment No.    )

Filed by the Registrant  ☒                             Filed by a Party other than the Registrant  ☐

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☐	Preliminary Proxy Statement
☐	Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))
☐	Definitive Proxy Statement
☒	Definitive Additional Materials
☐	Soliciting Material under § 240.14a-12

Dyne Therapeutics, Inc.

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

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P.O. BOX 8016, CARY, NC 27512-9903
Dyne Therapeutics, Inc. Important Notice Regarding the Availability of Proxy Materials for the Stockholder Meeting to be held on May 26, 2021
For Stockholders as of April 1, 2021
This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. This is not a ballot. You cannot use this notice to vote your shares. We encourage you to access and review all of the important information contained in the proxy materials before voting.
To view the proxy materials, and to obtain directions to virtually attend meeting, go to: www.proxydocs.com/DYN
To vote your proxy while visiting this site, you will need the 12 digit control number in the box below.
Under United States Securities and Exchange Commission rules, proxy materials do not have to be delivered in paper. Proxy materials can be distributed by making them available on the Internet.
For a convenient way to view proxy materials and VOTE go to www.proxydocs.com/DYN
Have the 12 digit control number located in the shaded box above available when you access the website and follow the instructions.
The Notice, Proxy Statement and Annual Report can be viewed online. If you want to receive a paper or e-mail copy of the proxy materials, you must request them. There is no charge to you for requesting a copy. In order to receive a paper package in time for this year’s meeting, you must make this request on or before May 14, 2021.
To order paper materials, use one of the following methods.
INTERNET www.investorelections.com/DYN
TELEPHONE (866) 648-8133
* E-MAIL paper@investorelections.com
When requesting via the Internet or telephone you will need the 12 digit control number located in the shaded box above.
* If requesting material by e-mail, please send a blank e-mail with the 12 digit control number (located above) in the subject line. No other requests, instructions OR other inquiries should be included with your e-mail requesting material.
Dyne Therapeutics, Inc.
Meeting Type: Annual Meeting of Stockholders Date: Wednesday, May 26, 2021 Time: 09:00 AM, Eastern Time
Place: Annual Meeting to be held live via the Internet - please visit www.proxydocs.com/DYN for more details.
You must register to attend the meeting online and/or participate at www.proxydocs.com/DYN
SEE REVERSE FOR FULL AGENDA

Dyne Therapeutics, Inc.
Annual Meeting of Stockholders
THE BOARD OF DIRECTORS RECOMMENDS A VOTE: FOR PROPOSALS 1 AND 2
PROPOSAL
1. The election of two Class I directors, each to serve for a three-year term expiring at the 2024 annual meeting of stockholders and until his or her respective successor has been duly elected and qualified.
1.01 Lawrence Klein, Ph.D.
1.02 Catherine Stehman-Breen, M.D.
2. The ratification of the appointment of Deloitte & Touche LLP as our independent registered public accounting firm for the fiscal year ending December 31, 2021.
Note: The transaction of any other business that may properly come before the 2021 Annual Meeting or any adjournment or postponement thereof.
THIS IS NOT A VOTABLE BALLOT
This is an overview of the more complete proxy materials that are available to you on the Internet.