DSGN · Design Therapeutics, Inc.

The shares subject to the option vest in equal monthly installments over 12 months following June 9, 2026 provided that the shares subject to the option will in any case be fully vested on the date of the Company's next annual meeting of stockholders.

The shares subject to the option vest in equal monthly installments over 12 months following June 9, 2026 provided that the shares subject to the option will in any case be fully vested on the date of the Company's next annual meeting of stockholders.

The shares subject to the option vest in equal monthly installments over 12 months following June 9, 2026 provided that the shares subject to the option will in any case be fully vested on the date of the Company's next annual meeting of stockholders.

The shares subject to the option vest in equal monthly installments over 12 months following June 9, 2026 provided that the shares subject to the option will in any case be fully vested on the date of the Company's next annual meeting of stockholders.

The shares subject to the option vest in equal monthly installments over 12 months following June 9, 2026 provided that the shares subject to the option will in any case be fully vested on the date of the Company's next annual meeting of stockholders.

The shares subject to the option vest in equal monthly installments over 12 months following June 9, 2026 provided that the shares subject to the option will in any case be fully vested on the date of the Company's next annual meeting of stockholders.

The shares subject to the option will vest in equal monthly installments over 12 months following March 31, 2026.

The shares subject to the option will vest in equal monthly installments over 36 months following March 31, 2026.

The shares subject to the option will vest as follows: 20% of the shares will vest on January 1, 2027, 20% of the shares will vest in equal monthly installments over the following 12 months, 30% of the shares will vest in equal monthly installments over the following 12 months, and 30% of the shares will vest in equal monthly installments over the following 12 months.

The shares subject to the option will vest as follows: 20% of the shares will vest on January 1, 2027, 20% of the shares will vest in equal monthly installments over the following 12 months, 30% of the shares will vest in equal monthly installments over the following 12 months, and 30% of the shares will vest in equal monthly installments over the following 12 months.

The shares subject to the option will vest in equal monthly installments over 36 months following September 9, 2025.

The shares subject to the option will vest as follows: 20% of the shares will vest on January 1, 2027, 20% of the shares will vest in equal monthly installments over the following 12 months, 30% of the shares will vest in equal monthly installments over the following 12 months, and 30% of the shares will vest in equal monthly installments over the following 12 months.

The shares subject to the option will vest as follows: 20% of the shares will vest on January 1, 2027, 20% of the shares will vest in equal monthly installments over the following 12 months, 30% of the shares will vest in equal monthly installments over the following 12 months, and 30% of the shares will vest in equal monthly installments over the following 12 months.

On September 1, 2023, the Reporting Person was granted an option to purchase 525,000 shares of common stock. 25% of the shares subject to the option would vest on August 25, 2024, and thereafter the balance would vest in equal monthly installments over the following 36 months, provided that, as an additional condition, no shares under the option would vest until the Issuer achieved a specific performance condition. On December 9, 2025, the Issuer's Board of Directors deemed that the performance condition had been met, resulting in vesting of the option as to 295,312 shares. The remainder of the unvested shares subject to the option shall vest monthly through August 25, 2027 subject to the continuous service of the Reporting Person through each such date.

On September 1, 2023, the Reporting Person was granted an option to purchase 525,000 shares of common stock. 25% of the shares subject to the option would vest on August 25, 2024, and thereafter the balance would vest in equal monthly installments over the following 36 months, provided that, as an additional condition, no shares under the option would vest until the Issuer achieved a specific performance condition. On December 9, 2025, the Issuer's Board of Directors deemed that the performance condition had been met, resulting in vesting of the option as to 295,312 shares. The remainder of the unvested shares subject to the option shall vest monthly through August 25, 2027 subject to the continuous service of the Reporting Person through each such date.

The shares subject to the option will vest in equal monthly installments over 36 months following September 9, 2025.

The shares subject to the option will vest in equal monthly installments over 12 months following September 9, 2025.

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.

Logos Global Management LP is the investment advisor of private funds, including Logos Opportunities Fund II LP ("LOF II"). Logos Opportunities GP LLC ("GP I") is the general partner of LOF II. The Reporting Person is the Managing Member of GP I. 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 shares subject to the option vest in equal monthly installments over 12 months following June 10, 2025 provided that the shares subject to the option will in any case be fully vested on the date of the Company's next annual meeting of stockholders.

The shares subject to the option vest in equal monthly installments over 12 months following June 10, 2025 provided that the shares subject to the option will in any case be fully vested on the date of the Company's next annual meeting of stockholders.

The shares subject to the option vest in equal monthly installments over 12 months following June 10, 2025 provided that the shares subject to the option will in any case be fully vested on the date of the Company's next annual meeting of stockholders.

The shares subject to the option vest in equal monthly installments over 12 months following June 10, 2025 provided that the shares subject to the option will in any case be fully vested on the date of the Company's next annual meeting of stockholders.

The shares subject to the option vest in equal monthly installments over 12 months following June 10, 2025 provided that the shares subject to the option will in any case be fully vested on the date of the Company's next annual meeting of stockholders.

The shares subject to the option vest in equal monthly installments over 12 months following June 10, 2025 provided that the shares subject to the option will in any case be fully vested on the date of the Company's next annual meeting of stockholders.

The shares subject to the option will vest as follows: 25% of the shares will vest on April 16, 2026 and the balance of the shares will vest in equal monthly installments thereafter over the following 36 months.

The shares subject to the option will vest as follows: 20% of the shares will vest on January 1, 2026, 20% of the shares will vest in equal monthly installments over the following 12 months, 30% of the shares will vest in equal monthly installments over the following 12 months, and 30% of the shares will vest in equal monthly installments over the following 12 months.

25% of the shares subject to the option vest on January 1, 2026 and the balance will vest in equal monthly installments thereafter over a three year period.

The shares subject to the option will vest as follows: 20% of the shares will vest on January 1, 2026, 20% of the shares will vest in equal monthly installments over the following 12 months, 30% of the shares will vest in equal monthly installments over the following 12 months, and 30% of the shares will vest in equal monthly installments over the following 12 months.

The shares subject to the option will vest as follows: 20% of the shares will vest on January 1, 2026, 20% of the shares will vest in equal monthly installments over the following 12 months, 30% of the shares will vest in equal monthly installments over the following 12 months, and 30% of the shares will vest in equal monthly installments over the following 12 months.

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.

The shares subject to the option vest in equal monthly installments over 12 months following June 13, 2024 provided that the shares subject to the option will in any case be fully vested on the date of the Company's next annual meeting of stockholders.

The shares subject to the option vest in equal monthly installments over 12 months following June 13, 2024 provided that the shares subject to the option will in any case be fully vested on the date of the Company's next annual meeting of stockholders.

The shares subject to the option vest in equal monthly installments over 12 months following June 13, 2024 provided that the shares subject to the option will in any case be fully vested on the date of the Company's next annual meeting of stockholders.

The shares subject to the option vest in equal monthly installments over 12 months following June 13, 2024 provided that the shares subject to the option will in any case be fully vested on the date of the Company's next annual meeting of stockholders.

The shares subject to the option vest in equal monthly installments over 12 months following June 13, 2024 provided that the shares subject to the option will in any case be fully vested on the date of the Company's next annual meeting of stockholders.

The shares subject to the option vest in equal monthly installments over 12 months following June 13, 2024 provided that the shares subject to the option will in any case be fully vested on the date of the Company's next annual meeting of stockholders.

The weighted average purchase price for the transaction reported was $3.6187, and the range of prices were between $3.43 and $3.72. Upon request by the SEC staff, the Issuer, or any security holder of the Issuer, full information regarding the number of shares sold at each separate price will be provided.

The Reporting Person is trustee of the trust.

The shares subject to the option will vest as follows: 20% of the shares will vest on January 1, 2025, 20% of the shares will vest in equal monthly installments over the following 12 months, 30% of the shares will vest in equal monthly installments over the following 12 months, and 30% of the shares will vest in equal monthly installments over the following 12 months.

The shares subject to the option will vest as follows: 20% of the shares will vest on January 1, 2025, 20% of the shares will vest in equal monthly installments over the following 12 months, 30% of the shares will vest in equal monthly installments over the following 12 months, and 30% of the shares will vest in equal monthly installments over the following 12 months.

The shares subject to the option will vest as follows: 25% of the shares will vest on November 1, 2024 and the balance will vest in equal monthly installments thereafter over a three year period.

The shares subject to the option will vest as follows: 25% of the shares will vest on October 1, 2024 and the balance will vest in equal monthly installments thereafter over a three year period.

The price reported in column 4 is a weighted average price. The shares were purchased at a range of prices between $2.33 and $2.38. Upon request by the Securities and Exchange Commission 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.