Connie Winslow is deaf. When she was old enough to attend school, she began having fainting spells, which her teachers and parents noticed happened when she became excited. One Christmas she was so thrilled with her gifts, that she promptly fainted. Her
Connie Winslow is deaf. When she was old enough to attend school, she began having fainting spells, which her teachers and parents noticed happened when she became excited. One Christmas she was so thrilled with her gifts, that she promptly fainted. Her parents took her to the emergency room, where doctors assured them, as they had in the past, that there wasn’t a problem. The spells continued and Connie became able to predict the attacks, telling her parents that her head hurt before the spells
Her parents took her to a neurologist, who checked Connie’s heart and diagnosed Long Q-T syndrome with deafness. This condition was also known as Lange-Nielsen syndrome.
The physician explained that this is a severe form of long-QT syndrome, which is an inherited heartbeat irregularity that can be fatal. Seven genes can cause long Q-T syndrome. The Winslows
(parents) visited a medical geneticist, who discovered that each had a mild, heartbeat irregularity that did not produce symptoms. Connie’s parents also had normal hearing. Connie’s younger brother Jim was also hearing-impaired and suffered night terrors, but had so far not fainted during the day. After a more complete examination and genetic testing the doctors realized that he had the full syndrome. A younger sister, Tina, was still a baby, and was tested. She did not have either form of the family’s illness; her heartbeat was normal.
QUESTIONS:
a.) What phenomena apply to the condition in this family?
b.) How is the inheritance pattern of jervell and Lange-Mielsen syndrome similar to that familial hypercholesterolemia?
c.) How possible is it that Tina would not inherit either the serious or asymptomatic form?
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