LIMITED POWER OF ATTORNEY FOR
                        SECTION 16 REPORTING OBLIGATIONS

        Know all by these presents, that the undersigned hereby makes,
constitutes and appoints each of Douglas Fambrough, Michael Todisco and Jack 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
undersigned is no longer required to file Forms 3, 4, and 5 with respect to the
undersigned's holdings of and transactions in securities issued by the Company,
unless earlier revoked by the undersigned in a signed writing delivered to the
foregoing attorneys-in-fact.

        IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to
be executed as of this 14th day of June, 2016.

                                        /s/ David Madden
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                                                  Signature

                                        David Madden
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                                                  Print Name