Lexeo Therapeutics, Inc. - Form 3 Filing and Power of Attorney

This filing includes a Form 3, which reports initial beneficial ownership of securities, for Laura Sepp-Lorenzino, a director at Lexeo Therapeutics, Inc. The filing also includes a Limited Power of Attorney, dated April 27, 2026, appointing Youjin Choi, Carole Rosenberg, and James Reilly as attorneys-in-fact. These attorneys are authorized to execute and file necessary Section 16 forms (Forms 3, 4, and 5) and any amendments thereto regarding the ownership, acquisition, or disposition of Company securities. This power of attorney remains in effect until Sepp-Lorenzino is no longer required to file such forms, unless revoked earlier. The filing indicates that the attorneys-in-fact are not assuming Sepp-Lorenzino's compliance responsibilities under Section 16 of the Securities Exchange Act of 1934.