EXHIBIT 24
POWER OF ATTORNEY
KNOW ALL MEN BY THESE PRESENTS, that the undersigned hereby
constitutes and appoints Kevin Gillis his true and lawful attorney-in-fact, with
full power of substitution, to sign any and all instruments, certificates and
documents that may be necessary, desirable or appropriate to be executed on
behalf of himself as an individual or in his capacity as a direct or indirect
general partner, director, officer, member or manager of any partnership,
corporation or limited liability company, pursuant to section 13 or 16 of the
Securities Exchange Act of 1934, as amended (the "Exchange Act"), and any and
all regulations promulgated thereunder, and to file the same, with all exhibits
thereto, and any other documents in connection therewith, with the Securities
and Exchange Commission, and with any other entity when and if such is mandated
by the Exchange Act or by the Financial Industry Regulatory Authority, granting
unto said attorney-in-fact full power and authority to do and perform each and
every act and thing necessary, desirable or appropriate, fully to all intents
and purposes as he might or could do in person, thereby ratifying and confirming
all that said attorney-in-fact, or his substitutes, may lawfully do or cause to
be done by virtue hereof. Each of the undersigned may execute this power of
attorney in separate counterparts, and each counterpart shall be deemed to be an
original instrument. This agreement shall be effective as to each of the
undersigned as of the date signed by that signatory.
IN WITNESS WHEREOF, this Power of Attorney has been signed as of the 16th day of
January, 2014.
/s/ Mark Levin
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Mark Levin
/s/ Kevin P. Starr
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Kevin P. Starr
/s/ Robert I. Tepper
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Robert I. Tepper
