Fourth-year law student Mark Lee died of natural causes in November, the Chief Medical Examiner said.

His cause of death was an abnormal heart rhythm known as a cardiac arrhythmia, which can occur when electrical impulses coordinating heartbeats don’t work properly, according to the Mayo Clinic.

The arrhythmia was due to hyponatremic dehydration, the medical examiner said. Hyponatremia occurs when there are abnormally low sodium levels in the blood, according to the Mayo Clinic.

Lee was 35 years old and had been taking courses part time at GW when he was found dead in his off-campus apartment on Nov. 30.

Lee had been sick with flu-like symptoms for several days before his death but seemed to be improving, his mother, Susan West, said this week.

West said that in the time since her son’s death, friends have been memorializing him by naming their children and pets after him, and have helped take care of West and her husband by including them in family activities. After a large snowfall, a friend of Lee’s came by to shovel their sidewalk, West said.

“They have been so incredibly kind,” she said. “They gave us a reason to get up.”

She also said Lee’s best friend since middle school was planning to launch a clothing line in Lee’s memory and the proceeds would be put towards a scholarship for the University of North Carolina Tar Heels, Lee’s favorite basketball team.

Plans for a memorial at GW are also in the works, she said.

“We always thought our son was amazing – just so smart and funny and thoughtful and loving,” she said. “He meant so much to us.”

A native of Newport News, Va., Lee was pursuing a career in business and contract law, and had worked at the global medical device company K2M Group Holdings Inc. in Leesburg, Va. since 2010.

He graduated from Virginia Tech in 2002 with a degree in communications and a minor in political science. He also took classes at the University of South Carolina and worked as a paralegal before deciding to go to law school.

Lee is the 10th student to die over the last 18 months. His death was the second in the law school last academic year, after a second-year student died by suicide in November.