Heidi Sinclair, the Bill & Melinda Gates Foundation's chief communications officer, is leaving her position at the end of the month.

A Seattle native, she has directed public relations since joining the foundation in September 2007. Her job description includes "protecting and advancing the foundation's reputation, increasing awareness of foundation issues, and overseeing our external and internal communications."

In a brief e-mail today, Sinclair said she is starting her own consultancy in Seattle, adding that she is "sad to leave the foundation, but very excited about the business I will build."

A Gates Foundation spokesperson confirmed her departure at the end of February.

Sinclair came to the foundation from public relations firm Burson-Marsteller, where she was president and CEO for Europe. During her tenure, as the size of the Gates Foundation doubled to about 700 employees, she built the foundation's current communications team and applied principles of corporate PR, striving for a uniform message presented in a controlled way to select media.

And while the Gates Foundation has tried to tighten control of its public image, critics say it still lacks openness and transparency. The foundation has cited its creation of outside advisory panels, an annual letter from Bill Gates and an overhaul of its Web site in response.

The foundation is currently conducting an executive search to replace Sinclair, who reports directly to Chief Executive Jeff Raikes.