X0306 4 2016-01-25 0 0001374690 ZAFGEN, INC. ZFGN 0001451612 Booth Bruce C/O ATLAS VENTURE FUND VII, L.P., 25 FIRST STREET, SUITE 303 CAMBRIDGE MA 02141 1 0 1 0 Common Stock 2016-01-25 4 A 0 4424 7.91 A 4638028 D These securities were issued in lieu of cash fees under the Non-Employee Director Compensation Policy pursuant to a Restricted Stock Agreement and the restrictions lapse over a period of one year starting January 1, 2016 on a quarterly basis in arrears. The Reporting Person previously reported 5,632,730 shares directly held by Atlas Venture Fund VII, L.P. ("Atlas Venture"). On March 24, 2015, Atlas Venture distributed in-kind 1,000,000 shares pro rata to its limited partners. The Reporting Person now reports 4,632,730 shares directly held by Atlas Venture and disclaims beneficial ownership of all such shares except to the extent of his pecuniary interest, if any, therein. /s/ Laurie Burlingame, Attorney-In-Fact 2016-01-27