X0306 4 2021-09-21 0 0001590750 Viridian Therapeutics, Inc.\DE VRDN 0001802528 Fairmount Funds Management LLC 2001 MARKET STREET, SUITE 2500 PHILADELPHIA PA 19103 1 0 1 0 0001830383 Fairmount Healthcare Fund GP LLC 2001 MARKET STREET, SUITE 2500 PHILADELPHIA PA 19103 1 0 0 1 See Remarks 0001830382 Fairmount Healthcare Fund II GP LLC 2001 MARKET STREET, SUITE 2500 PHILADELPHIA PA 19103 1 0 0 1 See Remarks 0001686157 Fairmount Healthcare Fund L.P. 2001 MARKET STREET, SUITE 2500 PHILADELPHIA PA 19103 1 0 0 1 See Remarks 0001769651 Fairmount Healthcare Fund II L.P. 2001 MARKET STREET, SUITE 2500 PHILADELPHIA PA 19103 1 0 0 1 See Remarks Common Stock 5859 I Fairmount Healthcare Fund LP Common Stock 2021-09-21 4 P 0 909000 11.00 A 938233 I Fairmount Healthcare Fund II LP Series A Non-Voting Convertible Preferred Stock Common Stock 1466673.33 21999 I Fairmount Healthcare Fund LP Series A Non-Voting Convertible Preferred Stock Common Stock 7413170.64 111192 I Fairmount Healthcare Fund II LP Fairmount Funds Management LLC and Fairmount Healthcare Fund GP LLC have voting power and investment power over the shares of Common Stock and Series A Non-Voting Convertible Preferred Stock held by Fairmount Healthcare Fund LP ("Fund I"). They disclaim beneficial ownership of securities held by Fund I for purposes of Rule 16a-1(a)(2), except to the extent of their pecuniary interest therein. Fairmount Funds Management LLC and Fairmount Healthcare Fund II GP LLC have voting power and investment power over the shares of Common Stock and Series A Non-Voting Convertible Preferred Stock held by Fairmount Healthcare Fund II LP ("Fund II"). They disclaim beneficial ownership of securities held by Fund II for purposes of Rule 16a-1(a)(2), except to the extent of their pecuniary interest therein. Following stockholder approval of the conversion of Series A Non-Voting Convertible Preferred Stock into shares of Common Stock, each share of Series A Non-Voting Convertible Preferred Stock is convertible into shares of Common Stock at any time at the option of the holder thereof, into 66.67 shares of Common Stock, subject to certain limitations, including that a holder of Series A Non-Voting Convertible Preferred Stock is prohibited from converting shares of Series A Non-Voting Convertible Preferred Stock into shares of Common Stock if, as a result of such conversion, such holder, together with its affiliates, would beneficially own more than 19.99% of the total number of shares of Common Stock issued and outstanding immediately after giving effect to such conversion. The Reporting Persons may each be deemed a director by deputization of Issuer by virtue of the fact that each of Peter Harwin and Tomas Kiselak serve on the board of directors of Issuer and are also each a Managing Member of Fairmount Funds Management LLC. /s/ Chris W. Trester, Attorney-in-fact for Fairmount Funds Management LLC 2021-09-23 /s/ Chris W. Trester, Attorney-in-fact for Fairmount Healthcare Fund GP LLC 2021-09-23 /s/ Chris W. Trester, Attorney-in-fact for Fairmount Healthcare Fund II GP LLC 2021-09-23 /s/ Chris W. Trester, Attorney-in-fact for Fairmount Healthcare Fund LP 2021-09-23 /s/ Chris W. Trester, Attorney-in-fact for Fairmount Healthcare Fund II LP 2021-09-23