Jett, who began suffering from seizures at the age of two and was reportedly diagnosed with Kawasaki disease as a toddler, had been found unconscious in a bathroom in the family's holiday home in the Bahamas.
He had later been taken to Rand Memorial Hospital, Freeport, where he was pronounced dead on January 2.
In the new study, researchers have claimed to identify new genes, which appear to make some children more susceptible to the disease, a serious illness of young children that often leads to coronary artery disease.
This is the first genetic study of an infectious disease to look at the whole of the genome, rather than just selected genes.
Researchers from UC San Diego School of Medicine Department of Pediatrics joined an international research team, including colleagues from The University of Western Australia, the Genome Institute of Singapore, Emma Children's Hospital, The Netherlands, and Imperial College London, UK.
The research team studied naturally occurring genetic variation in almost 900 cases of Kawasaki disease from these countries.
"KD tends to run in families, suggesting that there are genetic components to disease risk," said Jane C. Burns, M.D., professor and Chief, Division of Allergy, Immunology, and Rheumatology, UC San Diego Department of Pediatrics.
"We have been trying to understand the step by step development of this disease (pathogenesis) and the chain of events leading to it, using a biological approach but with limited success. This robust, systematic genome wide study is simply letting the genetics tell us what are the key genes in KD pathogenesis. Without this research these newly discovered genes of interest might have continued to remain hidden," Burns added.
The researchers found that genes involved in cardiovascular function and inflammation may be particularly important and some seem to function together.
According to them, these findings will lead to new diagnostics and better treatment and may be informative about adult cardiovascular disease as well.
However, the findings do not yet prove that the new genes are functionally involved. Other genetic variants may be important, especially in different ethnic groups.
The researchers are planning detailed studies of the function of these genes and larger collaborative studies including East Asian populations, who are at particular risk of Kawasaki disease, with 1 in 150 Japanese children affected.
The study is published in PLoS Genetics.