The hospital where the boy was on life support before he died said he had pneumonia and not the dreaded avian flu virus that has killed about 70 people in Asia, CNN said. However, there was no confirmation of the cause of death from the Turkish health ministry.
Three of the teen's siblings, who also were taken ill, have tested negative for the disease, while tests on two others have not been returned.
Officials said it was not clear what killed Mehmet Ali Kocyigit.
"The disease is not caused by bird flu or any other flu virus," said Turan Buzgan, a health ministry official.