13D Filing: RA Capital Management and Dicerna Pharmaceuticals Inc (DRNA)

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¹ Represents 2,428,571 shares
of the common stock (“Common Stock”) of Dicerna Pharmaceuticals, Inc. (the “Issuer”) and 2,159,965 shares
of the Common Stock issuable upon conversion of Preferred Stock (as defined below) which constitute approximately 19.94% of the
class outstanding. The percentage calculation assumes that there are currently 20,848,503 outstanding shares of the Common Stock
of the Issuer, based on the Issuer’s Form 10-Q for the quarterly period ended September 30, 2017 as filed with the Securities
and Exchange Commission (“SEC”) on November 2, 2017.