Kathryn L. "Kate" Steffen

Steven A. Sigsbury specializes in tax and estate planning, estate and trust administration, fiduciary responsibility, and business and real estate planning. Steven’s laid-back personality allows him to relate to clients and instill a sense of trustworthiness at the outset of any engagement. Steven analyzes and simplifies complex problems and offers clients individualized solutions. As a tax and estate planner, Steven works with clients to develop tax-efficient estate plans that accompli...

Jeremy B. Root is a top attorney recognized by Best Lawyers in the practice area(s) of Business Organizations (including LLCs and Partnerships) and Real Estate Law. Jeremy B., who practices law in Fairfax, Virginia, has been recognized since 2025. This recognition is based on an exhaustive peer-review survey, reflecting the high esteem in which Jeremy B. is held by other top lawyers in the same geographic and legal practice area.

Mustafa Ostrander is a top attorney recognized by Best Lawyers in the practice area(s) of Energy Regulatory Law. Mustafa, who practices law in Washington, District of Columbia, has been recognized since 2026. This recognition is based on an exhaustive peer-review survey, reflecting the high esteem in which Mustafa is held by other top lawyers in the same geographic and legal practice area.

Jane C. Horvath is a top attorney recognized by Best Lawyers in the practice area(s) of Privacy and Data Security Law. Jane C., who practices law in Washington, District of Columbia, has been recognized since 2024. This recognition is based on an exhaustive peer-review survey, reflecting the high esteem in which Jane C. is held by other top lawyers in the same geographic and legal practice area.

Sara W. Koblitz advises FDA-regulated clients on a range of issues with a particular focus on Hatch-Waxman patent and exclusivity, biosimilars, and the Orange Book. She helps drug and device manufacturers in various stages of product development and guides clients through the applicable regulatory requirements with respect to applications and submissions, device classification, potential exclusivities, promotional issues, and post-marketing requirements. Ms. Koblitz also counsels cosmetics, f...

Nathan J. Muyskens is a top attorney recognized by Best Lawyers in the practice area(s) of Criminal Defense: White-Collar. Nathan J., who practices law in Washington, District of Columbia, has been recognized since 2026. This recognition is based on an exhaustive peer-review survey, reflecting the high esteem in which Nathan J. is held by other top lawyers in the same geographic and legal practice area.

Prudence Avery Upton is a top attorney recognized by Best Lawyers in the practice area(s) of Family Law. Prudence Avery, who practices law in Rockville, Maryland, has been recognized since 2018. This recognition is based on an exhaustive peer-review survey, reflecting the high esteem in which Prudence Avery is held by other top lawyers in the same geographic and legal practice area.

For more information, please visit www.gibsondunn.com/lawyer/walker-helgi-c/ .

Ms. Javitt provides strategic FDA regulatory advice for leading medical device, diagnostics, pharmaceutical, biological products, and human cellular, and tissue-based products (HCT/Ps) throughout the product life cycle and has successfully resolved disputes at both the pre- and post-market stage. She also has significant experience advising clinical laboratories on FDA and CLIA requirements for laboratory developed tests. Ms. Javitt’s experience prior to joining Hyman, Phelps & McNa...

Mark J. Riedy is a top attorney recognized by Best Lawyers in the practice area(s) of Mergers and Acquisitions Law. Mark J., who practices law in Washington, District of Columbia, has been recognized since 2023. This recognition is based on an exhaustive peer-review survey, reflecting the high esteem in which Mark J. is held by other top lawyers in the same geographic and legal practice area.