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                            October 6, 2020

       Marcio Souza
       Chief Executive Officer
       Praxis Precision Medicines, Inc.
       One Broadway, 16th Floor
       Cambridge, MA 02142

                                                        Re: Praxis Precision
Medicines, Inc.
                                                            Registration
Statement on Form S-1
                                                            Filed September 25,
2020
                                                            File No. 333-249074

       Dear Mr. Souza:

              We have reviewed your registration statement and have the
following comment. In our
       comment, we may ask you to provide us with information so we may better
understand your
       disclosure.

              Please respond to this letter by amending your registration
statement and providing the
       requested information. If you do not believe our comment applies to your
facts and
       circumstances or do not believe an amendment is appropriate, please tell
us why in your
       response.

              After reviewing any amendment to your registration statement and
the information you
       provide in response to the comment, we may have additional comments.

       Registration Statement on Form S-1

       License Agreement with RogCon, page 161

   1.                                                   We note your response
to prior comment 1. Please further revise your disclosure to define
                                                        "Additional Milestone
Payments" and clarify your reference to all such payments
                                                        becoming due under your
collaboration agreement with Ionis.
               We remind you that the company and its management are
responsible for the accuracy
       and adequacy of their disclosures, notwithstanding any review, comments,
action or absence of
       action by the staff.

              Refer to Rules 460 and 461 regarding requests for acceleration.
Please allow adequate
       time for us to review any amendment prior to the requested effective
date of the registration
       statement.
 Marcio Souza
Praxis Precision Medicines, Inc.
October 6, 2020
Page 2

       You may contact Gary Newberry at 202-551-3761 or Kate Tillan at
202-551-3604 if you
have questions regarding comments on the financial statements and related
matters. Please
contact Courtney Lindsay at 202-551-7237 or Christine Westbrook at 202-551-5019
with any
other questions.



                                                        Sincerely,
FirstName LastNameMarcio Souza
                                                        Division of Corporation
Finance
Comapany NamePraxis Precision Medicines, Inc.
                                                        Office of Life Sciences
October 6, 2020 Page 2
cc:       William D. Collins, Esq.
FirstName LastName