DAVID S. GRAYZEL - 15 Jan 2026 Form 4 Insider Report for Q32 Bio Inc. (QTTB)

Role: Director
Signature: /s/ Eric Bell, Attorney-in-Fact
Issuer symbol: QTTB
Transactions as of: 15 Jan 2026
Net transactions value: +$44,998
Form type: 4
Filing time: 30 Jan 2026, 19:00:06 UTC
Previous filing: 27 Oct 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
GRAYZEL DAVID S.	Director	Q32 BIO INC., 830 WINTER STREET, WALTHAM	/s/ Eric Bell, Attorney-in-Fact	30 Jan 2026	0001732786

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	QTTB	Stock Option (Right to Buy)	Award	$44,998	+16,363		$2.75	16,363	15 Jan 2026	Common Stock	16,363	$3.60	Direct	F1, F2

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	This option was granted to the Reporting Person, a director of the Issuer pursuant to the 2024 Stock Option and Incentive Plan and pursuant to the Issuer's non-employee director compensation policy. This option shall vest in four equal quarterly installments as of the last date of each calendar quarter subject to the Reporting Person's continued service through such date and represents the Reporting Person's election to receive stock options in lieu of cash retainer fees. Due to administrative oversight this option award initially was not reported.
F2	This option was granted to the Reporting Person, a director of the Issuer. The proceeds of any sale of shares of common stock issued to the Reporting Person upon exercise of this option will be transferred to Atlas Venture Life Science Advisors, LLC and as such, the Reporting Person disclaims ownership of such securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, except to the extent of his pecuniary interest therein, if any.

Content

This option was granted to the Reporting Person, a director of the Issuer pursuant to the 2024 Stock Option and Incentive Plan and pursuant to the Issuer's non-employee director compensation policy. This option shall vest in four equal quarterly installments as of the last date of each calendar quarter subject to the Reporting Person's continued service through such date and represents the Reporting Person's election to receive stock options in lieu of cash retainer fees. Due to administrative oversight this option award initially was not reported.

This option was granted to the Reporting Person, a director of the Issuer. The proceeds of any sale of shares of common stock issued to the Reporting Person upon exercise of this option will be transferred to Atlas Venture Life Science Advisors, LLC and as such, the Reporting Person disclaims ownership of such securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, except to the extent of his pecuniary interest therein, if any.