WHEN UNIVERSITY of the Sciences students return from winter break, they will have a new president.

The university yesterday announced the resignation of Helen Giles-Gee after 2 1/2 years. Giles-Gee, who became the school's first female president and 22nd president overall when she assumed the post in July 2012, will step down Dec. 31. Board of Trustees chairman Marvin Samson will serve as interim president.

"At this time and after serious reflection, I have decided to leave University of the Sciences," Giles-Gee wrote in a statement. "I am honored to have served as president and will hold this university dear in my heart."

A university spokesman said Giles-Gee was not available for comment. He did not elaborate on the reason for her departure, except to say that it was for personal reasons.

Giles-Gee joined the West Philadelphia institution with more than 30 years of experience in higher education, having served as president of Keene State College in New Hampshire from 2005 to 2012, and as provost at Rowan University. She had been biology chair at Cheyney University, the nation's oldest historically black college.

"On behalf of the board, I want to thank Dr. Giles-Gee for her years of service and many contributions as our 22nd president," Samson said in a statement. "She served USciences well at a difficult period of transition and addressed the objectives identified by the board of trustees during her tenure."

In October, the university - known as the nation's first college of pharmacy - agreed to purchase Wilson Elementary School from the Philadelphia School District to convert it to student housing and retail.

Before hiring Giles-Gee, the university went nearly a year without a permanent president following the retirement of Philip Gerbino in August 2011.