Gertjan’s practice focuses on technology and patents, where his background in science serves him well. His practice spans all fields of technology, including chemical, electrical, mechanical, computer, life sciences and pharmaceutical technology.

Gertjan litigates before national courts, the EPO as well as in arbitration. Most of his work is cross-border in nature, and he has extensive experience in conducting and coordinating multi-jurisdictional litigation.

Besides litigation, Gertjan also advises on licensing, FTO, IP strategy and IP structuring in contract research and joint R&D (both private/private and public/private).

Clients in Legal 500 praise the patent litigation group at De Brauw headed by Gertjan as "first class. The team is responsive, engaged and a pleasure to work with. They have a depth of litigation experience across a range of industry/technology sectors."

Gertjan is described as "a stellar IP litigator" and "a pleasure to work with – bright, responsive and commercial". "A master strategist who doesn't lose sight of the details. "A 'top player in the field' highlighted for his strategic thinking" according Chambers. His scientific background is also appreciated by clients, as reported by Chambers: “He’s not just a lawyer but also a technician. He understands technology quickly, is thorough and detailed, and very easy to work with.”