Cause of 'Gossip Girl' actor Michelle Trachtenberg's death explained, media reportsbr br US actor Michelle Trachtenberg died as a result of complications from diabetes mellitus, according to multiple news outlets sourcing the New York City medical examiner's office. Trachtenberg was 39 years old when she died in February of this year in New York. According to reports the medical examiner’s office confirmed it was toxicology results rather than an autopsy that offered more information about her death.