Kawasaki disease is a serious illness primarily affecting young children, typically those under five years of age. This condition involves inflammation within the body’s blood vessels, particularly the medium-sized arteries. Of particular concern is the inflammation of the coronary arteries, which supply blood to the heart muscle. Kawasaki disease stands as the most common cause of acquired heart disease among children in many developed nations.
Is Kawasaki Disease Inherited?
Kawasaki disease is not a classic inherited genetic disorder, meaning it does not result from a single gene mutation passed directly from parent to child. It does not follow typical Mendelian inheritance patterns. Research into family histories has not revealed a straightforward inheritance pattern. Therefore, having a family member with the condition does not mean it will be directly inherited like other genetic illnesses.
Genetic Susceptibility and Immune Response
While not directly inherited, certain genetic variations can increase a child’s likelihood of developing Kawasaki disease. These genetic factors appear to influence how an individual’s immune system responds to various triggers. This predisposes some children to an exaggerated inflammatory response, which is a hallmark of the disease.
Specific genes associated with immune regulation and inflammation have been identified as playing a role in this susceptibility. For instance, a variation in the ITPKC gene has been linked to an increased risk. This gene provides instructions for an enzyme that helps limit the activity of immune cells called T cells. A variation in ITPKC may impair the body’s ability to properly regulate T cell activity, potentially leading to the excessive inflammation seen in Kawasaki disease.
Other genes, such as FCGR2A, CASP3, BLK, CD40, and ORAI1, are also connected to susceptibility. For example, FCGR2A variations affect how immune cells are activated and are observed in both European and Asian populations. The higher incidence of Kawasaki disease in East Asian populations, particularly in Japan, further suggests a genetic predisposition.
Environmental Triggers
The precise cause of Kawasaki disease remains unknown, but it is widely believed that an environmental trigger interacts with a child’s genetic predisposition. Researchers suspect that an infection, likely viral or bacterial, serves as this trigger. Despite extensive study, a single specific infectious agent has not been definitively identified.
Kawasaki disease is not contagious and does not spread from person to person. Cases often show seasonal and geographical clustering, appearing in late winter and early spring. Studies indicate that various environmental factors, including temperature, wind patterns, and precipitation, might influence these clusters, suggesting multiple triggers.
Understanding Risk for Families
While Kawasaki disease is not inherited in a straightforward manner, there is a recognized familial tendency. If one child in a family has had Kawasaki disease, their siblings have a slightly increased risk of developing the condition. In Japan, for instance, siblings of an affected child show an approximate tenfold higher relative risk compared to the general population. For parents who have had a child with Kawasaki disease, their risk of having another child with the condition is about twice that of the general population.
Despite these increased risks within families, the overall likelihood of subsequent children developing the disease is not as high as in diseases with direct genetic inheritance. The presence of both sibling and parental history points to the role of genetic susceptibility. Recurrence in the same child is also possible, although it occurs in a small percentage of cases, between 1.5% and 4%.