X0206 3 2020-09-16 0 0001818794 Dyne Therapeutics, Inc. DYN 0001824542 Beskrovnaya Oxana C/O DYNE THERAPEUTICS, INC. 830 WINTER STREET WALTHAM MA 02451 0 1 0 0 See Remarks Stock Option (right to buy) 1.03 2030-01-05 Common Stock 98426 D Stock Option (right to buy) 5.54 2030-07-30 Common Stock 44493 D Stock Option (right to buy) 5.54 2030-07-30 Common Stock 46954 D The option was granted on January 6, 2020. The shares underlying the option vest over four years, with 25% of the shares vesting on January 27, 2021 and the remaining shares vesting in equal quarterly installments thereafter. The option was granted on July 31, 2020. The shares underlying the option vest over four years in equal quarterly installments through July 31, 2024 provided that no shares shall vest prior to January 27, 2021. The option was granted on July 31, 2020. The shares underlying the option vest over four years in equal quarterly installments through July 31, 2024 provided that no shares shall vest prior to January 27, 2021. Senior Vice President, Head of Research Exhibit Index: 24.1 Power of Attorney /s/ Richard Scalzo, Attorney-in-Fact 2020-09-16