Shiloh Winslow is deaf. In early childhood, she began having fainting spells, especially when she became excited. When she fainted while opening Christmas gifts, her parents took her to the hospital, where doctors said, again, that there wasn't a problem. As the spells continued, Shiloh became able to predict the attacks, telling her parents that her head hurt beforehand. Her parents took her to a neurologist, who checked Shiloh's heart and diagnosed long QT syndrome with deafness, a severe form of inherited heartbeat irregularity (see Reading 2.2 ). Ten different genes can cause long QT syndrome. The doctor told them of a case from 1856: a young girl, called at school to face the headmaster for an infraction, became so agitated that she dropped dead. The parents were not surprised; they had lost two other children to great excitement. The Winslows visited a medical geneticist, who discovered that each parent had a mild heartbeat irregularity that did not produce symptoms. Shiloh's parents had normal hearing. Shiloh's younger brother Pax was also hearing-impaired and suffered night terrors, but had so far not fainted during the day. Like Shiloh, he had the full syndrome. Vivienne, still a baby, was also tested. She did not have either form of the family's illness; her heartbeat was normal. Today, Shiloh and Pax are treated with beta blocker drugs, and each has an implantable defibrillator to correct a potentially fatal heartbeat. Shiloh's diagnosis may have saved her brother's life. 1. a. Which of the following applies to the condition in this family? genetic heterogeneity pleiotropy variable expressivity incomplete dominance v.a phenocopy How is the inheritance pattern of this form of long QT syndrome similar to that of familial hypercholesterolemia? How is it possible that Vivienne did not inherit either the serious or asymptomatic form of the illness? Do the treatments for the condition affect the genotype or the phenotype? 5. Barnabas Collins has congenital erythropoietic porphyria, and his wife Angelique is a carrier of ALA dehydratase deficiency. What is the chance that, if they have a child, he or she will have a porphyria? .

1. Shiloh Winslow is deaf. In early childhood, she began having
fainting spells, especially when she became excited. When she
fainted while opening Christmas gifts, her parents took her to
the hospital, where doctors said, again, that there wasn't a
problem. As the spells continued, Shiloh became able to predict
the attacks, telling her parents that her head hurt beforehand.
Her parents took her to a neurologist, who checked Shiloh's
heart and diagnosed long QT syndrome with deafness, a severe
form of inherited heartbeat irregularity (see
Reading 2.2
). Ten different genes can cause long QT syndrome. The doctor
told them of a case from 1856: a young girl, called at school to
face the headmaster for an infraction, became so agitated that
she dropped dead. The parents were not surprised; they had lost
two other children to great excitement. The Winslows visited a
medical geneticist, who discovered that each parent had a mild
heartbeat irregularity that did not produce symptoms. Shiloh's
parents had normal hearing. Shiloh's younger brother Pax was
also hearing-impaired and suffered night terrors, but had so far
not fainted during the day. Like Shiloh, he had the full
syndrome. Vivienne, still a baby, was also tested. She did not
have either form of the family's illness; her heartbeat was
normal. Today, Shiloh and Pax are treated with beta blocker
drugs, and each has an implantable defibrillator to correct a
potentially fatal heartbeat. Shiloh's diagnosis may have saved
her brother's life.
1.
a. Which of the following applies to the condition in this
family?
genetic heterogeneity
pleiotropy

2. variable expressivity
incomplete dominance
v.a phenocopy
How is the inheritance pattern of this form of long QT
syndrome similar to that of familial hypercholesterolemia?
How is it possible that Vivienne did not inherit either the
serious or asymptomatic form of the illness?
Do the treatments for the condition affect the genotype or the
phenotype?
5.
Barnabas Collins has congenital erythropoietic porphyria, and
his wife Angelique is a carrier of ALA dehydratase deficiency.
What is the chance that, if they have a child, he or she will have
a porphyria?