Rational treatment of cardiac hypertrophy requires understanding the underlying causes of the disease. But doctors know little about the causes of this illness in children, so no diagnostic tests have yet been developed. “Although the condition is rare in children, the prognosis is even worse. Kids with cardiac hypertrophy are often candidates for heart transplantation“, says Jonathan Seidman, Harvard Medical School Professor.
Researchers therefore extracted DNA from 84 individuals diagnosed with the condition before age 15. Just 33 of those children had family histories of cardiac hypertrophy. Using a novel chip technology, they sequenced the 10 suspect genes. The team identified mutations in 25 of the 51 children without family histories and in 21 of the 33 children with family histories.
“I think it’s remarkable that we found mutations in nearly 50 percent of the kids who didn’t have family histories,” says Christine Seidman, also Harvard Medical School Professor. Her team took a closer look at the genes of these patients’ parents. Eleven pairs of parents agreed to participate in the study. In 7 cases, one parent harbored the same mutation as his or her child. Though these adults assumed their hearts were fine, echocardiograms revealed thickening of the muscle in some cases.
“Labs have done work on the genetic underpinnings of cardiac hypertrophy in adults, but few thought that the research applied to children,” says Seidman. “For years, doctors assumed the two conditions were clinically distinct.” According to Christine Seidman, 3 to 4 percent of adults have cardiac hypertrophy. Data from the Framingham Heart Study suggest that mutations in 10 genes account for 1/5 or 1/6 of those cases. Most of the genes implicated encode “sarcomere” proteins, which make up the heart’s contractile apparatus.
“We still don’t know why the children presented symptoms so much earlier than their parents,” says Jonathan Seidman. “We suspect that other genes must influence the disease presentation.”
MEDICA.de; Source: Harvard Medical School