An 18-year-old MIT freshman was discovered dead in his dorm room on Tuesday afternoon.

Satto Tonegawa, a son of a Nobel Prize-winning MIT professor and a cum laude graduate from Milton Academy in Milton, Mass., is the second MIT undergraduate to be found dead in a dormitory this school year.

University and law enforcement officials declined to provide details about the circumstances of his death.

The death does not appear to be suspicious or involve foul play, said Cara O’Brien, a spokesperson for the Middlesex district attorney’s office.

O’Brien said the state Office of the Chief Medical Examiner will conduct an autopsy to find out the cause of death.

MIT’s student newspaper, The Tech, reported that Tonegawa had not been seen for a week prior to his death. Some students said they had noticed a strange odor near his room.

“This is a very sad situation, and the entire MIT community shares a deep sense of loss and grief,” MIT Chancellor Eric Grimson said in a statement. “Our thoughts go out to the family, friends, classmates, and dormmates of Satto, as well as to the graduate resident tutors, housemasters, and others in the student-life system who knew and worked with Satto.”

Susumu Tonegawa, Satto’s father, received the Nobel Prize in Physiology or Medicine in 1987 for work on the genetic mechanism that creates the diversity of antibodies. He could not be reached for comment.

Hidde Tonegawa, Satto’s brother, said in a statement to the Boston Globe that the family is struggling to understand what happened.

“Everyone’s still in shock,” he told The Globe.

Those who knew Tonegawa in high school said he was not only bright and talented, but also kind and sincere.

“If you didn’t know him, you probably thought he was quiet,” said Doriane Ahia ’15, a classmate of Tonegawa’s at Milton. “But he was a really smart, funny, and nice guy. He had a lot of friends who cared about him, and that just shows how great a person he was.”

Ahia said she had a few classes with him in their freshman year.

“It’s surreal that I will never see him again,” Ahia said. “You never expect something like this would happen to someone you know.”

Grant M. Jones ’14, who knew Tonegawa since the third grade, agreed.