Deck 11: Common Childhood-Onset Genetic Disorders

Question 1

What is the most likely explanation for the variability in expression of disease severity for cystic fibrosis?

A)The ethnicity of the patient
B)The specific CFTR gene mutation inherited
C)The presence of other nongenetic lung or pancreatic problems
D)The length of trinucleotide repeat sequences in the first exon of the CFTR gene

Answer 1

The specific CFTR gene mutation inherited

Question 2

Which statement regarding Duchenne muscular dystrophy (DMD) is true?

A)Females are not affected.
B)Because DMD is X-linked recessive, females are affected, and males are carriers.
C)Because DMD is X-linked recessive, males are affected, and females are carriers.
D)The sons of women who are older than age 40 when pregnant are at an increased risk for DMD.

Answer 2

Because DMD is X-linked recessive, males are affected, and females are carriers.

Question 3

How does the drug Endari reduce the manifestations of sickle cell disease?

A)Promoting faster red blood cell production
B)Increasing the concentration of fetal hemoglobin (HbF)
C)Reducing oxidate stress and increasing the life span of red blood cells
D)Correcting the mutation of one allele so that the person has sickle cell trait instead of sickle cell disease

Answer 3

Reducing oxidate stress and increasing the life span of red blood cells

Question 4

What health advantage does cystic fibrosis confer on the person who has it?

A)Decreased risk for type 1 diabetes mellitus
B)Decreased risk for tuberculosis
C)Decreased risk for anemia
D)Decreased risk for typhoid

Question 5

How is sickle cell trait different from sickle cell disease?

A)People with sickle cell disease are homologous for the mutation, whereas those with sickle cell trait are heterozygous for the mutation.
B)People with sickle cell trait are homologous for the mutation, whereas those with sickle cell disease are heterozygous for the mutation.
C)Sickle cell disease results from an inherited mutation, and sickle cell trait results from an acquired mutation.
D)Sickle cell trait results from an inherited mutation, and sickle cell disease results from an acquired mutation.

Question 6

Which feature or factor is the best predictor for delay of complications in a person who has sickle cell disease (SCD)?

A)Male gender
B)20% or greater of HbF
C)Having survived malaria
D)Living in a geographic area that has cold winters

Question 7

Which additional health problem commonly develops in boys with Duchenne muscular dystrophy?

A)Arthritis
B)Hypertension
C)Diabetes mellitus
D)Chronic heart failure

Question 8

A 21-year-old woman who has two brothers with Duchenne muscular dystrophy asks whether carrier status testing is appropriate for her. What is the best response?

A)"Testing could be beneficial because your risk for being a carrier is nearly 100%."
B)"Testing could be beneficial because your risk for being a carrier is approximately 50%.
C)"Testing is not necessary because you would have expressed some symptoms of the disease by this time if you were a carrier."
D)"Testing is not necessary because the spontaneous mutation rate for this genetic problem is high and likely to be why your brothers have the disease."

Question 9

Which type of testing is most commonly used to diagnose sickle cell disease?

A)Hematocrit and hemoglobin levels
B)Hemoglobin electrophoresis
C)Genetic mutation analysis
D)Sweat chloride analysis

Question 10

Zoe, a 20-year-old woman, shows signs of mild muscle weakness. She has two first cousins on her mother's side who died of Duchenne's muscular dystrophy (DMD).Whichexplanation regarding Zoe's situation is most likely?

A)Zoe is a heterozygote showing partial expression
B)Zoe and her cousins shared similar environmental risks.
C)The muscle weakness is related to Zoe's lack of exercise in her "girly-girl" lifestyle.
D)Zoe is homozygous for DMD, with a defective dystrophin gene inherited from both parents.

Question 11

Which tissues are most commonly affected by mutation of the CFTR gene?

A)Eyes and ears
B)Brain and intestines
C)Lungs and pancreas
D)Kidneys and long bones

Question 12

Which type of testing is most commonly used to diagnose cystic fibrosis (CF)?

A)Mucus protein electrophoresis
B)Genetic mutation analysis
C)Sweat chloride analysis
D)Stool analysis

Question 13

Which ethnic group has the highest incidence of sickle cell disease (SCD)?

A)Ashkenazi Jews
B)Asian Americans
C)African Americans
D)French Canadians from Quebec

Question 14

Which ethnic group has the highest incidence of cystic fibrosis (CF)?

A)Asian Americans
B)African Americans
C)Hispanic Americans
D)European Americans

Question 15

What health advantage does sickle cell trait or disease confer on the person who has it?

A)Decreased risk for type 1 diabetes mellitus
B)Decreased risk for hypercholesterolemia
C)Decreased risk for fulminating cholera
D)Decreased risk for malaria

Question 16

What is the explanation for creatine kinase (CK) levels in a 14-year-old boy with Duchenne muscular dystrophy being much lower now than they were 5 years ago?

A)His disease is improving.
B)He now performs passive rather than active exercise.
C)Most of the muscle tissue has already been destroyed.
D)The disease is probably Becker muscular dystrophy (BMD) rather than Duchenne muscular dystrophy.

Question 17

Why does Duchenne muscular dystrophy (DMD) have poor reproductive fitness?

A)Most affected individuals typically do not have children.
B)Fifty percent of mutations of the dystrophin gene are deletions.
C)The loss of functional adhesion proteins prevents reproduction.
D)The expression of disease severity is highly variable among adults

Question 18

Which specific type of genetic problem causes sickle cell disease?

A)Deletion of an exon
B)Deletion of an intron
C)Unbalanced translocation
D)Single-nucleotide polymorphism

Question 19

Which relative of a patient who has cystic fibrosis has the correct risk for being a cystic fibrosis carrier?

A)Sister 0%
B)Mother 50%
C)Father 100%
D)Brother 100%

Question 20

Awoman whose hemoglobin S levels are less than 1% has a brother with sickle cell disease, and both parents have been diagnosed as carriers for the disorder. She asks what her risks are of having a child with sickle cell disease. What is the best response?

A)"Because you do not have the trait, you cannot have a child with sickle cell disease regardless of your partner's sickle cell status."
B)"Because both your parents have the trait, it is possible for you to have a child with sickle cell disease if your partner actually has the disease."
C)"Because your brother actually has sickle cell disease, the risk for your children having sickle cell disease is 50% with each pregnancy."
D)"Because you are a woman, your daughters will each have a 50% risk for having the disease, and all of your sons will be carriers of the trait."

Question 21

Which phenotypic feature associated with achondroplasia has variable expression?

A)Disproportionally short extremities
B)Larger-than-average head size
C)Prominent forehead
D)Hydrocephaly

Question 22

How is hemophilia A (classical hemophilia) different from hemophilia B?

A)Symptoms of hemophilia B are not present at birth, but those of hemophilia A are.
B)In hemophilia B, the affected gene is on an autosome instead of the X chromosome.
C)The clotting factor problem in hemophilia B is a deficiency of factor IX rather than factor VIII.
D)The physiologic effect on the partial thromboplastin time is more profound with hemophilia than with hemophilia B.

Question 23

Which problem or symptom is associated with type 1 diabetes but not with type 2 diabetes?

A)Insulitis
B)Polydipsia
C)Weight gain
D)Hyperglycemia

Question 24

Which statement regarding classic hemophilia is true?

A)Females are not affected.
B)Because hemophilia is X-linked recessive, females are affected, and males are carriers.
C)Because hemophilia is X-linked recessive, males are affected, and females are carriers.
D)The sons of women who are older than age 40 when pregnant are at an increased risk for hemophilia.

Question 25

A 12-year-old girl was diagnosed with von Willebrand disease (VWD) when she developed profound anemia from very heavy menstrual periods. Her levels of von Willebrand (vWf) factor are normal. What specific type of von Willebrand disease is she most likely to have?

A)Type 1 VWD
B)Type 2 VWD
C)Type 3 VWD
D)Type 4 VWD

Question 26

Which result of genetic/genomic variation has the most support as a cause of asthma?

A)Decreased resistance to infectious microorganisms
B)Early childhood exposures to inhalation irritants (air pollution)
C)Increased inflammatory responses to environmental triggers
D)Mutations in frontal-lobe genes controlling attention-getting behavior

Question 27

Which factor has the greatest genetic influence in the development of type 1 diabetes mellitus?

A)Inheritance of the HLA-DR or HLA-DQ tissue types
B)Sedentary lifestyle coupled with childhood obesity
C)Mutation in the gene for pancreas development
D)Advanced maternal age at conception

Question 28

Which statement about achondroplasia is true?

A)Females are affected twice as often as males.
B)The affected infant's appearance at birth is normal.
C)The protein impaired by the mutation is the receptor for fibroblast growth factor.
D)Transmission is less of a problem among males with achondroplasia because they are usually infertile.

Question 29

Which form of von Willebrand disease (VWD) is most often diagnosed in early childhood?

A)Type 1 VWD
B)Type 2 VWD
C)Type 3 VWD
D)Type 4 VWD

Question 30

A son with achondroplasia is born to parents with no family history of the disease. What is the most likely explanation for the son's disorder?

A)The son is not biologically related to the mother.
B)The son is not biologically related to the father.
C)The gamete of one parent had a spontaneous mutation.
D)The son's DNA underwent a spontaneous mutation during the second trimester of pregnancy.

Question 31

For individuals who have increased genetic susceptibility for type 1 diabetes, what is the most common environmental trigger for disease expression?

A)Obesity and a sedentary lifestyle
B)Exposure to radiation
C)Premature birth
D)Viral infection

Question 32

Which health problem occurs at a higher rate among children with achondroplasia than among the general population?

A)Cognitive impairment
B)Hearing impairment
C)Color blindness
D)Sudden infant death syndrome

Question 33

Which statement regarding type 1 von Willebrand disease (VWD) is true?

A)Incomplete penetrance is common.
B)It represents the female form of hemophilia.
C)Carriers can transmit the disease to their children.
D)Males are affected twice as frequently as females.

Question 34

Which type of testing is most commonly used to diagnose classic hemophilia?

A)Hematocrit and hemoglobin levels
B)X-chromosome inactivation
C)Genetic mutation analysis
D)Factor VIII levels