Stories about: genetic penetrance

If I have the mutation, will I get the disease? New research looks at genetic ‘penetrance’

genetic penetranceRecently announced preliminary results of the BabySeq study included pathogenic or “likely pathogenic” variants linked to heart conditions in three apparently healthy babies. Two are being followed at Boston Children’s Hospital and have had cardiac testing. But is this testing necessary, and are these infants truly at risk? It’s too soon to tell.

Then, last week, a report from the Mayo Clinic raised an alarm about overzealous use of genetic testing in healthy individuals. After a 13-year-old boy died from a heart syndrome, about two dozen family members had genetic testing. All tested positive for variants in a gene linked to long-QT syndrome and were diagnosed with the disease. Yet none had cardiac symptoms, and only one had a positive EKG at any point — the boy’s brother, who had a defibrillator implanted. When the Mayo team reanalyzed the test results using a more up-to-date genetic database, they concluded the variant is harmless.

And this week, in Science Translational Medicine, researchers at Brigham and Women’s Hospital, Boston Children’s and Massachusetts General Hospital address the question: If people carry a genetic mutation linked to a condition, what are the chances they will develop that condition over time? As part of the genomes2people project, the researchers tested participants in two long-term population studies — the Framingham Heart Study and the Jackson Heart Study — for 56 genes representing 24 hereditary cancer and cardiac syndromes. They did not know the participants’ actual health status. As it turned out, carrying a mutation increased risk for the related disease 4.7-fold in African Americans and 6.4-fold in European Americans, who had longer follow-up. This was true regardless of family history.

Vector sat down with Nina Gold, MD, a senior resident in Pediatrics and Medical Genetics at Boston Children’s, for her perspective. Gold is a first author on this week’s report.

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