LIMITED POWER OF ATTORNEY FOR
                        SECTION 16 REPORTING OBLIGATIONS

        Know all by these presents, that the undersigned hereby makes,
constitutes and appoints each of James Weissman and John B. Green, or either of
them acting individually, and with full power of substitution, the undersigned's
true and lawful attorney-in-fact to:

        (1)     prepare, execute in the undersigned's name and on the
                undersigned's behalf, and submit to the U.S. Securities and
                Exchange Commission (the "SEC") a Form ID, including amendments
                thereto, and any other documents necessary or appropriate to
                obtain codes and passwords enabling the undersigned to make
                electronic filings with the SEC of reports required by Section
                16(a) of the Securities Exchange Act of 1934 (the "Exchange
                Act") or any rule or regulation of the SEC;

        (2)     execute for and on behalf of the undersigned, in the
                undersigned's capacity as an officer and/or director of Dicerna
                Pharmaceuticals, Inc. (the "Company"), Forms 3, 4, and 5 in
                accordance with Section 16(a) of the Exchange Act and the rules
                thereunder;

        (3)     seek or obtain, as the undersigned's representative and on the
                undersigned's behalf, information on transactions in the
                Company's securities from any third party, including brokers,
                employee benefit plan administrators and trustees, and the
                undersigned hereby authorizes any such person to release any
                such information to the undersigned and approves and ratifies
                any such release of information;

        (4)     do and perform any and all acts for and on behalf of the
                undersigned which may be necessary or desirable to complete and
                execute any such Form 3, 4, or 5, complete and execute any
                amendment or amendments thereto, and timely file such form with
                the SEC and any stock exchange or similar authority; and

        (5)     take any other action of any type whatsoever in connection with
                the foregoing which, in the opinion of such attorney-in-fact,
                may be of benefit to, in the best interest of, or legally
                required by, the undersigned, it being understood that the
                documents executed by such attorney-in-fact on behalf of the
                undersigned pursuant to this Power of Attorney shall be in such
                form and shall contain such terms and conditions as such
                attorney-in-fact may approve in such attorney-in-fact's
                discretion.

        The undersigned hereby grants to each such attorney-in-fact full power
and authority to do and perform any and every act and thing whatsoever
requisite, necessary, or proper to be done in the exercise of any of the rights
and powers herein granted, as fully to all intents and purposes as the
undersigned might or could do if personally present, with full power of
substitution or revocation, hereby ratifying and confirming all that such
attorney-in-fact, or such attorney-in-fact's substitute or substitutes, shall
lawfully do or cause to be done by virtue of this power of attorney and the
rights and powers herein granted. The undersigned acknowledges that the
foregoing attorneys-in-fact, in serving in such capacity at the request of the
undersigned, are not assuming nor relieving, nor is the Company assuming nor
relieving, any of the undersigned's responsibilities to comply with Section 16
of the Exchange Act. The undersigned acknowledges that neither the Company nor
the foregoing attorneys-in-fact assume (i) any liability for the undersigned's
responsibility to comply with the requirement of the Exchange Act, (ii) any
liability of the undersigned for any failure to comply with such requirements,
or (iii) any obligation or liability of the undersigned for profit disgorgement
under Section 16(b) of the Exchange Act.

        This Power of Attorney shall remain in full force and effect until the
earliest of (a) the undersigned is no longer required to file Forms 3, 4, and 5
in accordance with Section 16(a) of the Exchange Act and the rules thereunder
with respect to the undersigned's holdings of and transactions in securities
issued by the Company, (b) neither James Weissman nor John B. Green is employed
by the Company, or (c) if revoked by the undersigned in a signed writing
delivered to each such attorney-in-fact.

        IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to
be executed as of this 10th day of November, 2016.

                                        /s/ Douglas M. Fambrough III
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                                                    Signature

                                        Douglas M. Fambrough III
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