Mia Farrow's son, Thaddeus Farrow, died Wednesday ... TMZ has learned.
Thaddeus died at Danbury Hospital in Connecticut, where Mia lives. Law enforcement confirmed he died from a life-threatening injury he suffered in his car ... and there was no foul play. There are no other details at this time. He was 27.
Mia adopted Thaddeus -- who was paraplegic due to polio -- in 1994 from Calcutta, India. He was one of 10 children Mia has adopted.
Thaddeus was adopted after Mia's split from Woody Allen.