The New York Post and other media outlets have in the past published unconfirmed reports that Travolta's son had autism, though the family has always maintained that he suffered from Kawasaki's. Autism is associated with seizures.
"There is a relationship between autism and seizures; as many as 40 percent of children and young adults with autism may experience seizure and adolescence is a particular time of vulnerability," said Dr. Bryan King, the director of child and adolescent psychiatry at Seattle Children's Hospital's Research Center for Health Services and Behavioral Research.
"There are hormonal changes that could increase the risk of seizure, and certainly there are ongoing brain changes that take place during adolescence, but no one knows why the risk increases in older children."
What little information is available on autopsy results further suggests that Jett Travolta may have been an epilepsy sufferer. If this is the case, he could have died from a massive seizure that led to a condition known as sudden unexplained death in epilepsy patients, or SUDEP.
Dr. Orrin Devinsky, director of the New York University Comprehensive Epilepsy Center, said SUDEP "is a relatively common problem among patients with uncontrolled tonic-clonic -- a.k.a. grand mal or convulsive -- seizures. In patients who have these frequently over a 10-year period, the incidence of SUDEP may be 8 percent or higher."
Dr. James Grisolia of the Epilepsy Foundation of San Diego, agreed that SUDEP could be a possibility, given the information at hand.
"We'll only really know once the autopsy results are out, as well as the statement from Jett's doctor, Mark Smith," Grisolia said.
But he added, "While the majority of adults and children with epilepsy live with their seizures well-controlled and can live up to their full human potential, there are rare, tragic cases of sudden, unexplained death in epilepsy [SUDEP] ... even well-controlled seizures sometimes break through, especially with forgetting to take medication, with excessive alcohol or sleep loss, or a serious second illness, such as a very bad flu or pneumonia."
Regardless of the cause, Travolta's attorney Ossi said that the family is now grieving. He added that the incident "is the worst pain any parent can experience, the loss of child."
Speaking for Travolta, Ossi said, "This is the worst day of his life."
In multiple interviews, Travolta and Preston have always attributed their son's illness to carpet-cleaning products they once used in the house.
"It was about seven years ago, and I was obsessive about cleaning -- his space being clean, so we constantly had the carpets cleaned," Travolta told Larry King in 2001. "And I think, between him, the fumes and walking around, maybe picking up pieces or something, he got what is rarely a thing to deal with, but it's Kawasaki syndrome."
"Jett's whole immune system shut down and he got really sick with high fevers -- 104 and 105. He developed a rash on his body and swollen lymph glands -- it was horrible," Preston told the U.K Mirror in 2004.
"Clearly, if anything about Jett's death could reflect badly on Scientology, the organization will go to great lengths to handle the problem," Kent said.
Scientology, the religion that Travolta has followed for about two decades, believes psychiatric drugs and counseling cause damage.