Security	Date	Code	Shares	Price	A/D	Owned after	D/I	Nature of ownership
Common Stock^F1,F3,F6	Apr 2, 2018	C	1,605,681	—	A	1,605,681	I	See footnote
Common Stock^F2,F4,F6	Apr 2, 2018	C	989,612	—	A	2,595,293	I	See footnote
Common Stock^F5	Apr 2, 2018	P	625,000	$16.00	A	3,220,293	I	See footnote

Table II — derivative securities

Security	Conv. / exercise price	Date	Code	Shares	A/D	Exercisable	Expires	Underlying	Underlying shares	Owned after	D/I
Series A Preferred Stock^F1,F6	—	Apr 2, 2018	C	1,605,681	D	—	—	Common Stock	1,605,681	0	I
Series B Preferred Stock^F2,F6	—	Apr 2, 2018	C	989,612	D	—	—	Common Stock	989,612	0	I

Explanation of responses

F1The Series A Preferred Stock of Homology Medicines, Inc. (the "Issuer") held of record by TLS Beta Pte. Ltd. ("TLS Beta") automatically converted into Common Stock on a 1:1 basis immediately prior to the closing of the initial public offering of the Issuer. Pursuant to the Amended and Restated Certificate of Incorporation of the Issuer, the shares of Series A Preferred Stock had been convertible, at the option of the holder, at any time into shares of Common Stock at an initial conversion rate equal to one share of Common Stock per share of Series A Preferred Stock, subject to adjustment and had no expiration date.
F2The Series B Preferred Stock of the Issuer held of record by TLS Beta automatically converted into Common Stock on a 1:1 basis immediately prior to the closing of the initial public offering of the Issuer. Pursuant to the Amended and Restated Certificate of Incorporation of the Issuer, the shares of Series B Preferred Stock had been convertible, at the option of the holder, at any time into shares of Common Stock at an initial conversion rate equal to one share of Common Stock per share of Series B Preferred Stock, subject to adjustment and had no expiration date.
F3Consists of 1,605,681 shares of Common Stock held of record by TLS Beta.
F4Consists of 989,612 shares of Common Stock held of record by TLS Beta.
F5Consists of 625,000 shares of Common Stock held of record by V-Sciences Investments Pte Ltd ("V-Sciences") which were purchased in the Issuer's initial public offering at a price of $16.00 per share. V-Sciences Investments Pte Ltd is a direct wholly-owned subsidiary of Temasek Life Sciences Private Limited. Temasek Life Sciences Private Limited ("TLS") is a direct wholly-owned subsidiary of Fullerton Management Pte Ltd ("FMPL"), which in turn is a direct wholly-owned subsidiary of Temasek Holdings (Private) Limited ("Temasek"). TLS, FMPL and Temasek may therefore be deemed to have or share beneficial ownership of the securities held by V-Sciences.
F6TLS Beta is a direct wholly-owned subsidiary of TLS. TLS is a direct wholly-owned subsidiary of FMPL, which in turn is a direct wholly-owned subsidiary of Temasek. TLS, FMPL and Temasek may therefore be deemed to have or share beneficial ownership of the securities held by TLS Beta.