X0306 5 2019-12-31 0 0 0 0001681087 AVROBIO, Inc. AVRO 0001741849 MACKAY GEOFFREY C/O AVROBIO, INC. 1 KENDALL SQ. BLDG 300, STE 201 CAMBRIDGE MA 02139 1 1 0 0 See Remarks Common Stock 2019-07-29 5 G 0 200000 0.00 D 145123 D Common Stock 200000 I By The Geoff R. MacKay Irrevocable Trust Common Stock 72604 I By son of reporting person Common Stock 72604 I By daughter of reporting person This transaction was a bona fide gift of common stock to The Geoff R. MacKay Irrevocable Trust. The reporting person disclaims beneficial ownership of the securities reported herein except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed an admission that the reporting person is the beneficial owner of the securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose. President and Chief Executive Officer /s/ Steven Avruch, as attorney-in-fact 2020-02-14