X0206 3 2020-10-15 0 0001689548 Praxis Precision Medicines, Inc. PRAX 0001597143 Clarus Lifesciences III, L.P. C/O CLARUS VENTURES, LLC 101 MAIN STREET, SUITE 1210 CAMBRIDGE MA 02142 0 0 1 0 0001620148 Clarus Ventures III GP, L.P. C/O CLARUS VENTURES, LLC 101 MAIN STREET, SUITE 1210 CAMBRIDGE MA 02142 0 0 1 0 0001762202 Blackstone Clarus III L.L.C. C/O THE BLACKSTONE GROUP INC. 345 PARK AVENUE NEW YORK NY 10154 0 0 1 0 0001464694 Blackstone Holdings I L.P. C/O THE BLACKSTONE GROUP INC. 345 PARK AVENUE NEW YORK NY 10154 0 0 1 0 0001484870 Blackstone Holdings II L.P. C/O THE BLACKSTONE GROUP INC. 345 PARK AVENUE NEW YORK NY 10154 0 0 1 0 0001464695 Blackstone Holdings I/II GP L.L.C. C/O THE BLACKSTONE GROUP INC. 345 PARK AVENUE NEW YORK NY 10154 0 0 1 0 0001393818 Blackstone Group Inc 345 PARK AVENUE NEW YORK NY 10154 0 0 1 0 0001404071 Blackstone Group Management L.L.C. C/O THE BLACKSTONE GROUP INC. 345 PARK AVENUE NEW YORK NY 10154 0 0 1 0 0001070844 SCHWARZMAN STEPHEN A C/O THE BLACKSTONE GROUP INC. 345 PARK AVENUE NEW YORK NY 10154 0 0 1 0 Common Stock 700934 I See Footnotes Series A Redeemable Convertible Preferred Stock Common Stock 3446711 I See Footnotes Series B Redeemable Convertible Preferred Stock Common Stock 2361198 I See Footnotes Series B-1 Redeemable Convertible Preferred Stock Common Stock 659116 I See Footnotes Series C Redeemable Convertible Preferred Stock Common Stock 261318 I See Footnotes Series C Redeemable Convertible Preferred Stock Common Stock 907378 I See Footnotes Series C-1 Redeemable Convertible Preferred Stock Common Stock 164832 I See Footnotes Reflects securities held directly by Clarus Lifesciences III, L.P. Clarus Ventures III GP, L.P. is the general partner of Clarus Lifesciences III, L.P. Blackstone Clarus III L.L.C. is the general partner of Clarus Ventures III GP, L.P. The sole member of Blackstone Clarus III L.L.C. is Blackstone Holdings II L.P. Reflects securities held directly by BSOF Parallel Master Fund L.P. Blackstone Strategic Opportunity Associates L.L.C. is the general partner of BSOF Parallel Master Fund L.P. Blackstone Holdings II L.P. is the sole member of Blackstone Strategic Opportunity Associates L.L.C. Blackstone Alternative Solutions L.L.C. is the investment manager of BSOF Parallel Master Fund L.P. Blackstone Holdings I L.P. is the sole member of Blackstone Alternative Solutions L.L.C. All series of Preferred Stock of the Issuer are convertible into common stock of the Issuer (the "Common Stock") on a 1-for-2.14 basis into the number of shares of Common Stock shown in column 3 at any time at the holder's election and automatically upon the closing of the Issuer's initial public offering. All series of Preferred Stock have no expiration date. The general partner of each of Blackstone Holdings I L.P. and Blackstone Holdings II L.P. is Blackstone Holdings I/II GP L.L.C. The sole member of Blackstone Holdings I/II GP L.L.C. is The Blackstone Group Inc. The sole holder of the Class C common stock of The Blackstone Group Inc. is Blackstone Group Management L.L.C. Blackstone Group Management L.L.C. is wholly-owned by Blackstone's senior managing directors and controlled by its founder, Stephen A. Schwarzman. Information with respect to each of the Reporting Persons is given solely by such Reporting Person, and no Reporting Person has responsibility for the accuracy or completeness of information supplied by another Reporting Person. Due to the limitations of the electronic filing system certain Reporting Persons are filing a separate Form 3. Each of the Reporting Persons (other than to the extent it directly holds securities reported herein) disclaims beneficial ownership of the securities held by the other Reporting Persons, except to the extent of such Reporting Person's pecuniary interest therein, and, pursuant to Rule 16a-1(a)(4) under the Securities Exchange Act of 1934, each of the Reporting Persons (other than to the extent it directly holds securities reported herein) states that the inclusion of these securities in this report shall not be deemed an admission of beneficial ownership of all of the reported securities for purposes of Section 16 or for any other purpose. CLARUS LIFESCIENCES III, L.P., By: Clarus Ventures III GP, L.P., its GP, By: Blackstone Clarus III, L.L.C., its GP, By: Blackstone Holdings II L.P., its M. Member, By: Blackstone Holdings I/II GP L.L.C., its GP, By: /s/ Tabea Y. Hsi, Managing Director 2020-10-15 CLARUS VENTURES III GP, L.P., By: Blackstone Clarus III, L.L.C., its GP, By: Blackstone Holdings II L.P., its managing member, By: Blackstone Holdings I/II GP L.L.C., its GP, By: /s/ Tabea Y. Hsi, Name: Tabea Y. Hsi, Title: Managing Director 2020-10-15 BLACKSTONE CLARUS III L.L.C., By: Blackstone Holdings II L.P., its managing member, By: Blackstone Holdings I/II GP L.L.C., its general partner, By: /s/ Tabea Y. Hsi, Name: Tabea Y. Hsi, Title: Managing Director 2020-10-15 BLACKSTONE HOLDINGS I L.P., By: Blackstone Holdings I/II GP L.L.C., its general partner, By: /s/ Tabea Y. Hsi, Name: Tabea Y. Hsi, Title: Managing Director 2020-10-15 BLACKSTONE HOLDINGS II L.P., By: Blackstone Holdings I/II GP L.L.C., its general partner, By: /s/ Tabea Y. Hsi, Name: Tabea Y. Hsi, Title: Managing Director 2020-10-15 BLACKSTONE HOLDINGS I/II GP L.L.C., By: /s/ Tabea Y. Hsi, Name: Tabea Y. Hsi, Title: Managing Director 2020-10-15 THE BLACKSTONE GROUP INC., By: /s/ Tabea Y. Hsi, Name: Tabea Y. Hsi, Title: Managing Director 2020-10-15 BLACKSTONE GROUP MANAGEMENT L.L.C., By: /s/ Tabea Y. Hsi, Name: Tabea Y. Hsi, Title: Managing Director 2020-10-15 /s/ Stephen A. Schwarzman 2020-10-15