Case six, you are seeing Frank, a 45-year-old man with no medical history and no family history of arrhythmias or sudden death. His youngest daughter, he has three children, had whole exome sequencing at birth because of multiple congenital abnormalities. She was found to have a mutation in the cardiac sodium channel, SCN5A or NAV1.5. She has no history of long QT syndrome and her QT interval on electrocardiogram is normal. Frank was tested and he also carries the mutation. He is completely asymptomatic and has a normal cardiac exam. The following is Frank's baseline electrocardiogram. Which of the following would you advise for Frank? A, his ECG shows long QT syndrome and he should be treated. B, he has no evidence of long QT syndrome, but further cardiac testing is required. C, his ECG may be an example of incomplete penetrance and no further evaluation or treatment are necessary. D, the mutation identified in Frank and his daughter probably does not cause long QT syndrome. And E, no further genetic screening of his family is necessary.

SCN5A gene

cardiac conditions

long QT syndrome

asymptomatic

genetic risks