Deck 8: Enzyme and Collagen Disorders

Question 1

Which action or behavior is considered an "executive function?"

A)Hopping on one foot
B)Learning the names of animals
C)Deciding what to give as a present
D)Counting the number of objects in a picture

Answer 1

Deciding what to give as a present

Question 2

If a man with Fabry disease has children with a woman who is a carrier for the disorder,what is the expected risk pattern?

A)All sons will be unaffected;all daughters will be carriers.
B)Sons have a 50% risk for being affected;all daughters will either be affected or carriers.
C)Daughters have a 50% risk for being affected;all sons will either be affected or carriers.
D)Each child of either gender has a 50% risk of being a carrier,a 25% risk of having the disease,and a 25% risk of neither being a carrier nor having the disease.

Answer 2

Sons have a 50% risk for being affected;all daughters will either be affected or carriers.

Question 3

What is the pathologic basis of Fabry disease?

A)Increased degradation of globotriaosylceramide
B)Increased accumulation of globotriaosylceramide
C)Deficiency in the number of liver lysosomes
D)Excessive number of liver lysosomes

Answer 3

Increased accumulation of globotriaosylceramide

Question 4

Which manifestation is a characteristic feature of untreated phenylketonuria (PKU)?

A)Increased skin pigmentation
B)Excessive urination
C)Fragile bones
D)Small stature

Question 5

Which ethnic group has the highest incidence of Gaucher disease?

A)Ashkenazi Jews
B)Asian Americans
C)American Indians
D)Individuals of Mediterranean descent

Question 6

Which manifestation in a teenage boy whose mother is a carrier for Fabry disease suggests the boy may have the disorder?

A)Hearing is hyperacute.
B)Opacity is present in both eyes.
C)Fasting blood glucose level is elevated.
D)Growth spurt results in a height 6 inches taller than his siblings.

Question 7

What is the expected result of a deficiency in the enzyme phenylalanine hydroxylase (PAH)?

A)High levels of phenylalanine;low levels of tyrosine
B)High levels of phenylalanine;high levels of tyrosine
C)Low levels of phenylalanine;low levels of tyrosine
D)Low levels of phenylalanine;high levels of tyrosine

Question 8

Which statement regarding lysosomal storage diseases is true?

A)A gene defect makes lysosomes unable to store degraded compounds.
B)Accumulation of stored iron results in cell,tissue,and organ dysfunction.
C)Defective enzymes result in the accumulation of potentially toxic substances.
D)Mutations in the genes coding for different types of collagen produce substances that are toxic to brain cells.

Question 9

Couples from which ethnic group would derive the greatest benefit from genetic testing for Tay-Sachs disease?

A)Ashkenazi Jews
B)Asian Americans
C)French Canadians from Quebec
D)Individuals of Mediterranean descent

Question 10

Which assessment finding in a 6-month-old child suggests a possible lysosomal storage disease?

A)Enlarged,palpable liver
B)Weight in the 95th percentile
C)Does not yet say "mama" or "dada"
D)Skin tone appears slightly lighter than that of either parent

Question 11

Which substance fails to form normally in individuals with Marfan syndrome?

A)Elastin
B)Glycogen
C)Collagen
D)Fibrillin

Question 12

Which therapeutic option has been found beneficial for patients with type I Gaucher disease?

A)Daily ingestion of oral sapropterin dihydrochloride (Kuvan)
B)Intravenous enzyme replacement with alpha-L iduronidase
C)Weekly phlebotomy with removal of excess red blood cells
D)Intravenous enzyme replacement with imiglucerase (Cerezyme)

Question 13

A woman who is a carrier for Fabry disease has children with a man who does not have the disorder.Their son has the disease and their daughter also has some symptoms of Fabry disease even though she could only have inherited one affected allele.What is the explanation for the daughter having some symptoms of Fabry disease?

A)The girl must have a different father than her brother.
B)The daughter is seeking the same attention that is given to her brother.
C)The inactivation of one X chromosome in female cells is a totally random event.
D)In addition to inheriting one affected allele,the daughter has developed a somatic mutation.

Question 14

Why is it important to diagnose type I Gaucher disease as soon as possible after birth?

A)Enzyme therapy can reduce complications for some patients.
B)When proper dietary management is instituted early,complications can be prevented.
C)Insulin therapy can result in prevention of the development of type 2 diabetes mellitus.
D)Prophylactic therapy with antibiotics can prevent early death from pneumonia and other infections.

Question 15

What is the expected outcome of pregnancy for women with phenylketonuria when the blood levels of phenylalanine are high throughout the pregnancy?

A)Most births are postmature
B)High incidence of infertility
C)Infant develops phenylketonuria
D)High incidence of cardiovascular birth defects

Question 16

How are the two mucopolysaccharide disorders Hurler Syndrome and Hunter Syndrome different?

A)Hurler syndrome is an autosomal dominant disorder,and Hunter syndrome is autosomal recessive.
B)Hunter syndrome is an autosomal dominant disorder,and Hurler syndrome is autosomal recessive.
C)Individuals with Hurler syndrome become cognitively impaired in early childhood,whereas those with Hunter syndrome often retain intellectual ability until later in life.
D)Individuals with Hunter syndrome become cognitively impaired in early childhood,whereas those with Hurler syndrome often retain intellectual ability until later in life.

Question 17

Which enzyme is deficient in individuals with Hurler syndrome?

A)Alpha-L iduronidase
B)Beta glucosidase
C)Iduronate sulfatase
D)Phenylalanine hydroxylase

Question 18

Which clinical manifestation in a 6-month-old infant is most diagnostic for Tay-Sachs disease?

A)Anemia and bruising
B)Enlarged liver and spleen
C)Cherry red spot on the retina
D)Progressive cognitive impairment

Question 19

Two 4-year-olds (Charlie and Lisa)have mucopolysaccharidosis I (MPSI).Charlie has severe dysmorphic features and many skeletal anomalies.Lisa has only mildly coarse features and slight developmental delay.What is the best explanation for these differences?

A)Skewed X inactivation allowed more paternal X expression for Lisa and more maternal X expression for Charlie.
B)Lisa's mother had better prenatal care,including good diet,exercise,and vitamins than Charlie's mother.
C)It is likely that Lisa has been misdiagnosed and really has MPSII.
D)The disorder has wide variability in expression of severity.

Question 20

Why does a newborn with a genetic enzyme deficiency have a normal phenotype at birth?

A)Metabolism during prenatal life is too slow to require full enzyme activity.
B)The deficient enzyme's activity was performed by maternal enzymes before birth.
C)During the fetal phase of life,the newborn was not exposed to the protein that the enzyme is responsible for degrading.
D)Although the newborn cannot synthesize the enzyme after birth,the initially stored enzyme performs its functions until the level is fully depleted.

Question 21

A son with osteogenesis imperfecta 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 father.
B)The son is not biologically related to the mother.
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 22

Which manifestation is most common among individuals with osteogenesis imperfecta type I?

A)Short stature
B)Premature birth
C)Skull deformities
D)Blue-tinged sclerae

Question 23

What is the most common cause of death among individuals with vascular Ehlers-Danlos (Ehlers-Danlos type IV)?

A)Respiratory impairment from kyphosis
B)Skin cancer (melanoma)
C)Intestinal rupture
D)Liver failure