FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person *   Bain Capital Life Sciences Investors, LLC 2. Date of Event Requiring Statement (Month/Day/Year) 04/11/2017 3. Issuer Name and Ticker or Trading Symbol Dicerna Pharmaceuticals Inc [DRNA] (Last) (First) (Middle) 200 CLARENDON STREET 4. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below) 5. If Amendment, Date Original Filed(Month/Day/Year) (Street) BOSTON, MA 02116 6. Individual or Joint/Group Filing(Check Applicable Line) ___ Form filed by One Reporting Person _X_ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Beneficially Owned

1.Title of Security (Instr. 4) 2. Amount of Securities Beneficially Owned (Instr. 4) 3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5) 4. Nature of Indirect Beneficial Ownership (Instr. 5)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.			SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Redeemable Convertible Preferred Stock	  (1)	  (1)	Common Stock	7,836,989	$ 3.19	I	See Footnotes (2) (3) (4) (5)

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Bain Capital Life Sciences Investors, LLC 200 CLARENDON STREET BOSTON, MA 02116	Â	  X	Â	Â
Bain Capital Life Sciences Partners, LP 200 CLARENDON STREET BOSTON, MA 02116	Â	  X	Â	Â
Bain Capital Life Sciences Fund, L.P. 200 CLARENDON STREET BOSTON, MA 02116	Â	  X	Â	Â
BCIP Life Sciences Associates, LP 200 CLARENDON STREET BOSTON, MA 02116	Â	  X	Â	Â
Schwartz Jeffrey Lawrence 200 CLARENDON STREET BOSTON, MA 02116	Â	  X	Â	Â
Koppel Adam 200 CLARENDON STREET BOSTON, MA 02116	  X	  X	Â	Â

Signatures

BAIN CAPITAL LIFE SCIENCES INVESTORS, LLC, By: /s/ Adam Koppel, Name: Adam Koppel, Title: Managing Director		04/13/2017
**Signature of Reporting Person		Date
BAIN CAPITAL LIFE SCIENCES PARTNERS, LP, By: Bain Capital Life Sciences Investors, LLC, its general partner, By: /s/ Adam Koppel, Name: Adam Koppel, Title: Managing Director		04/13/2017
**Signature of Reporting Person		Date
BAIN CAPITAL LIFE SCIENCES FUND, L.P., By: Bain Capital Life Sciences Partners, LP, its general partner, By: Bain Capital Life Sciences Investors, LLC, its general partner, By: /s/ Adam Koppel, Name: Adam Koppel, Title: Managing Director		04/13/2017
**Signature of Reporting Person		Date
BCIP LIFE SCIENCES ASSOCIATES, LP, By: Boylston Coinvestors, LLC, its general partner, By: /s/ Adam Koppel, Name: Adam Koppel, Title: Authorized Signatory		04/13/2017
**Signature of Reporting Person		Date
/s/ Jeffrey Schwartz		04/13/2017
**Signature of Reporting Person		Date
/s/ Adam Koppel		04/13/2017
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 5(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Each share of Redeemable Convertible Preferred Stock has a stated value of $100 (the "Stated Value") and accrues dividends daily at an initial rate of 12% per annum, subject to two rate reductions of 4% each upon the occurrence of certain milestone events. The Stated Value, as adjusted to give effect to such dividends, is referred to as the "Accrued Value." Each share of Redeemable Convertible Preferred Stock is convertible, at the option of the holder or, upon the occurrence of certain events, at the option of the Issuer, into a number of shares of the Issuer's Common Stock determined by dividing the Accrued Value by the conversion price. The Redeemable Convertible Preferred Stock is not convertible to the extent that such conversion would result in the beneficial owner of such Redeemable Convertible Preferred Stock and its affiliates owning in excess of 19.99% of the Issuer's voting power.
(2)	Bain Capital Life Sciences Investors, LLC ("BCI LS") is the general partner of Bain Capital Life Sciences Partners, LP ("BC LS P"), which is the general partner of Bain Capital Life Sciences Fund, L.P. ("BC LS"). As a result, BC LS P may be deemed to share voting and dispositive power with respect to the securities held by BC LS. BC LS holds 226,139 shares of Redeemable Convertible Preferred Stock.
(3)	BCIP Life Sciences Associates, LP (together with BC LS, the "Bain Life Sciences Entities"), whose general partner is Boylston Coinvestors, LLC, holds 23,861 shares of Redeemable Convertible Preferred Stock.
(4)	The governance, investment strategy and decision-making process with respect to the investments held by the Bain Life Sciences Entities is directed by BCI LS, whose managers are Jeffrey Schwartz and Adam Koppel. As a result, BCI LS, Mr. Schwartz and Dr. Koppel may each be deemed to share voting and dispositive power with respect to the securities held by the Bain Life Sciences Entities. BCI LS, Mr. Schwartz and Dr. Koppel each disclaim beneficial ownership of such securities except to the extent of their pecuniary interest therein.
(5)	Dr. Koppel is a director of the Issuer.

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