X0508 4 2023-08-28 0 0001807120 Design Therapeutics, Inc. DSGN 0001848372 William Arsani C/O DESIGN THERAPEUTICS, INC. 6005 HIDDEN VALLEY ROAD, SUITE 110 CARLSBAD CA 92011 1 0 0 0 0 Common Stock 2023-08-28 4 P 0 275000 2.15 A 1040000 I By Logos Global Master Fund LP Common Stock 2023-08-29 4 P 0 1960000 2.44 A 3000000 I By Logos Global Master Fund LP Common Stock 1217627 I By Logos Opportunities Fund II, L.P. Common Stock 814874 I By Logos SPV 1 LP The weighted average purchase price for the transaction was $2.15. The shares were purchased at a range of prices between $2.11 and $2.1677, inclusive. Upon request by the SEC staff, the Issuer, or any security holder of the Issuer, full information regarding the number of shares purchased at each separate price will be provided. Logos GP LLC ("Fund GP") is the general partner of Logos Global Master Fund LP (the "Fund"). The Reporting Person is the Managing Member of Fund GP. The Reporting Person disclaims beneficial ownership of these securities except to the extent of Reporting Person's pecuniary interest therein, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of all of the reported shares for purposes of Section 16 or for any other purpose. The weighted average purchase price for the transaction was $2.44. The shares were purchased at a range of prices between $2.29 and $2.50, inclusive. Upon request by the SEC staff, the Issuer, or any security holder of the Issuer, full information regarding the number of shares purchased at each separate price will be provided. Logos Global Management LP is the investment advisor of private funds, including Logos Opportunities Fund II LP ("LOF II") and Logos SPV 1 LP ("SPV 1"). Logos Opportunities GP LLC ("GP I") is the general partner of LOF II. Logos Opportunities II GP LLC ("GP II") is the general partner of SPV 1. The Reporting Person is the Managing Member of both GP I and GP II. The Reporting Person disclaims beneficial ownership of these securities except to the extent of Reporting Person's pecuniary interest therein, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of all of the reported shares for purposes of Section 16 or for any other purpose. /s/ Mustapha Parekh, Attorney-in-Fact 2023-08-30