Sec Form 3/A Filing - SR One Capital Fund I Aggregator LP @ Design Therapeutics, Inc. - 2021-03-25

FORM 3/A 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 SR One Capital Fund I Aggregator LP 2. Issuer Name and Ticker or Trading Symbol Design Therapeutics, Inc. [ DSGN] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 985 OLD EAGLE SCHOOL ROAD, SUITE 511 3. Date of Earliest Transaction (MM/DD/YY) 03/25/2021 (Street) WAYNE, PA19087 4. If Amendment, Date Original Filed (MM/DD/YY) 03/25/2021 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

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 Series A Preferred Stock ( 1 ) ( 2 ) ( 2 ) ( 2 ) Common Stock 4,439,839 D ( 3 ) Series B Preferred Stock ( 1 ) ( 2 ) ( 2 ) ( 2 ) Common Stock 936,637 D ( 3 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other SR One Capital Fund I Aggregator LP 985 OLD EAGLE SCHOOL ROAD, SUITE 511 WAYNE, PA19087 X SR ONE CAPITAL PARTNERS I, LP 985 OLD EAGLE SCHOOL ROAD, SUITE 511 WAYNE, PA19087 X SR ONE CAPITAL MANAGEMENT, LLC 985 OLD EAGLE SCHOOL ROAD, SUITE 511 WAYNE, PA19087 X Signatures SR ONE CAPITAL FUND I AGGREGATOR, LP,By: SR ONE CAPITAL PARTNERS I, LP,By: SR ONE CAPITAL MANAGEMENT, LLC,By: /s/ Simeon George, Member 03/30/2021 Signature of Reporting Person Date SR ONE CAPITAL PARTNERS I, LP, By: SR ONE CAPITAL MANAGEMENT, LLC, By: /s/ Simeon George, Member 03/30/2021 Signature of Reporting Person Date SR ONE CAPITAL MANAGEMENT, LLC, By: /s/ Simeon George, Member 03/30/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )This amendment is being filed to add SR One Capital Partners I, LP and SR One Capital Management, LLC as joint filers to the Form 3 filed by SR One Capital Fund I Aggregator, LP on March 25, 2021. ( 2 )All outstanding shares of Preferred Stock will automatically convert into shares of Common Stock at a rate of 1 share of Common Stock for each 1.63 shares of Preferred Stock, based on the conversion price currently in effect, at the Reporting Person's election and automatically upon the closing of the initial public offering of Design Therapeutics, Inc. (the "Issuer"). The Preferred Stock has no expiration date. ( 3 )The reported securities are held directly by SR One Capital Fund I Aggregator, LP. SR One Capital Partners I, LP is the general partner of SR One Capital Fund I Aggregator, LP, and SR One Capital Management, LLC is the general partner of SR One Capital Partners I, LP. Simeon George, M.D. is the managing member of SR One Capital Management, LLC. Each of SR One Capital Partners I, LP, SR One Capital Management, LLC and Mr. George may each be deemed to have shared power to vote or dispose of these shares, and each disclaims beneficial ownership of the shares except to the extent of any 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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