The study reports that 34.4% of children who developed dilated cardiomyopathy after myocarditis carried a cardiomyopathy gene variant, compared with 6.3% of control children. The authors say the difference was highly significant. Researchers compared 32 children with both dilated cardiomyopathy and myocarditis to children who had myocarditis without dilated cardiomyopathy and to heart-healthy controls.
Investigators describe a "double hit" model: a pathological cardiomyopathy mutation present from birth is the first hit, and an infection that reaches heart muscle cells is the second hit. The mutations reduce cardiac reserve and increase the chance of heart failure, recurrent myocarditis, and sudden cardiac death.
Steven E. Lipshultz is the corresponding author and a professor at the Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo. He called the study "a game changer." The genetics work was led by Stephanie Ware. The authors say clinicians who do not test for pathologic mutations will not know which patients face higher risk, and they advise action when testing shows concerning factors.
Difficult words
- dilated cardiomyopathy — enlarged heart disease causing weak heart muscle
- myocarditis — inflammation of the heart muscle
- variant — a different form of a gene
- control — person or group used for comparison in studiescontrol children, controls
- significant — statistically or clearly important in study results
- mutation — a permanent change in the DNA sequencemutations
- cardiac reserve — the heart's extra ability to work under stress
- double hit — two events that together cause a disease
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Discussion questions
- Do you think doctors should test children with myocarditis for genetic mutations? Why or why not?
- How does the "double hit" idea explain why some children develop heart failure after myocarditis?
