Teresa A. Mullin '90, a former Quincy House resident originally from Allentown, Penn., died yesterday of complications from cystic fibrosis.

Mullin, who served as executive editor of The Crimson in 1989, had been receiving treatment at the Royal Brompton hospital in London, England for three-and-a-half weeks. She had been in England for several months, attempting to attain citizenship so that she could be placed on a waiting list for a heart-lung transplant.

British doctors will not perform such transplants, often necessary for cystic fibrosis patients, on non-citizens. "She fought hard," her father, Edward Mullin, said yesterday. "She had an intense couple of weeks."

"Her death was unexpected," her mother, Patricia Mullin, said. "We loved her very much."

Mullin, known as Terri to many of her friends, was in England on a six-month British Universities visa, her father said. The visa allowed her to look for employment as a writer.

"Journalism was her main interest," her father said.

Mullin was born in 1969. She attended the Phillips Exeter Academy in Exeter, N.H.

While at Harvard, Mullin, a government major, served as an editor of The Crimson. She was Business School beat reporter, Faculty beat reporter and eventually executive editor.

Seth A. Gitell '91, former senior editor of The Crimson, praised her "incredible toughness" in investigative reporting.

"In her short life, she did a lot," Gitell said. "It was too soon."

"We are terribly sad at the news of Terri's death," said Crimson President Rebecca L. Walkowitz '92. "She was a dedicated member of The Crimson and a great friend to many here."

"She spoke highly and warmly of her Crimson experiences," her father said.

During the summer of 1989, Mullin interned as a business reporter for the Boston Globe. Her mentor, Teresa M. Hanafin, remembers her as "probably the most courageous person I ever met."

Hanafin said that Mullin covered some of the Globe's biggest business stories that summer, including the NYNEX telephone strike, the shutdown of the General Motors plant in Framingham and the migration of business ethics professors from the Harvard Business School.

She said that Mullin also wrote an op-ed piece for the Globe describing her experiences with cystic fibrosis and criticizing the U.S. medical establishment for not doing all it could to treat the disease.