X0202 SCHEDULE 13G/A 0001193125-20-038236 0001298709 XXXXXXXX LIVE 3 Common Stock, $0.00001 par value ("Common Stock") 03/31/2026 0001711279 Krystal Biotech, Inc. (the "Company") 501147102 2100 Wharton Street Suite 701 Pittsburgh PA 15203 Rule 13d-1(d) Krish S. Krishnan X1 0.00 3388283.00 0.00 3388283.00 3388283.00 N 11.5 IN Suma M. Krishnan X1 0.00 3388283.00 0.00 3388283.00 3388283.00 N 11.5 IN Krystal Biotech, Inc. (the "Company") 2100 Wharton Street, Suite 701, Pittsburgh, Pennsylvania, 15203 The Reporting Persons, Mr. Krish S. Krishnan and his wife, Mrs. Suma M. Krishnan, each filed a Schedule 13G on April 4, 2018, which were both then amended on February 19, 2019, and February 14, 2020 (the "Individual 13Gs"). The Reporting Persons are now reporting together on this Schedule 13G/A, which is deemed to be the 3rd Amendment to the Individual 13Gs. c/o KRYSTAL BIOTECH, INC. 2100 WHARTON STREET SUITE 701 PITTSBURGH, PA 15203 Mr. and Mrs. Krishnan are citizens of the United States of America. Y Each of the Reporting Persons may be deemed to be the beneficial owner of an aggregate 3,388,283 shares of the Company's Common Stock as set forth in more detail in response to Item 4(c) below. 11.5% The percentage was calculated in accordance with Rule 13d-3(d)(1)(i) promulgated under the Securities Exchange Act of 1934, as amended (the "Exchange Act") based on an aggregate total of 29,479,756 shares of Common Stock outstanding as of April 29, 2026, as reported by the Company in its Form 10-Q filed with the U.S. Securities and Exchange Commission on May 4, 2026. Krish S. Krishnan: 0 shares of Common Stock Suma M. Krishnan: 0 shares of Common Stock Krish S. Krishnan: 3,388,283 shares of Common Stock Suma M. Krishnan: 3,388,283 shares of Common Stock The reported securities are directly held as follows: (i) 1,475,253 shares of Common Stock directly owned by Krish S. Krishnan; (ii) 1,403,155 shares of Common Stock directly owned by Suma M. Krishnan; (iii) 90,000 shares of Common Stock that are directly owned by the SMK Trust FBO KSK, an irrevocable trust established by Mrs. Krishnan for the benefit of Mr. Krishnan who serves as a co-trustee and shares voting and dispositive power with a 3rd party co-trustee. These shares of Common Stock are not beneficially owned by Mrs. Krishnan but are included to disclose the aggregate holdings of both Reporting Persons; (iv) 90,000 shares of Common Stock that are directly owned by the Krishnan Spousal Trust, an irrevocable trust established by Mr. Krishnan for the benefit of Mrs. Krishnan who serves as a co-trustee and shares voting and dispositive power with a 3rd party co-trustee. These shares of Common Stock are not beneficially owned by Mr. Krishnan but are included to disclose the aggregate holdings of both Reporting Persons; (v) 50,000 shares of Common Stock owned by the Krishnan Family Trust, a revocable trust established for the benefit of Mr. and Mrs. Krishnan who share voting and investment control of the trust; (v) 158,525 shares of Common Stock issuable upon the exercise of stock options held by Mr. Krishnan; and (vi) 121,350 shares of Common Stock issuable upon the exercise of stock options held by Mrs. Krishnan. The Reporting Persons may be deemed to share beneficial ownership of the reported securities, but the filing of this Statement shall not be construed as an admission of such beneficial ownership for purposes of Section 13(d) or 13(g) of the Exchange Act or for any other purpose. Krish S. Krishnan: 0 shares of Common Stock Suma M. Krishnan: 0 shares of Common Stock Krish S. Krishnan: 3,388,283 shares of Common Stock Suma M. Krishnan: 3,388,283 shares of Common Stock See Item 4(c)(ii) above, which is incorporated herein by reference. Y N Y Y Y Y Y Exhibit 99.1 Joint Filing Agreement Krish S. Krishnan /s/ Krish S. Krishnan Krish S. Krishnan/Chariman & CEO 05/04/2026 Suma M. Krishnan /s/Suma M. Krishnan Suma M. Krishnan/Director, President R&D 05/04/2026