1.40: Diseases of Genetic Origin

1. A certain trait is expressed independent of gender and even though each person is not homozygous for the gene. This type of inheritance is best termed as:
   1. autosomal recessive
   2. autosomal dominant
   3. X-linked dominant
   4. X-linked recessive
   5. multifactorial
2. “Lyonization” is a process by
   1. Barr body analysis of cells is made
   2. chromosomes are displayed in metaphase cells
   3. phenylalanine is detected in urine
   4. amino acidurias are screened in newborns
   5. X-chromosome in each female’s cells is randomly inactivated
3. Organic acidurias occur as a result of:
   1. glycogen storage diseases
   2. aminoacidopathies
   3. errors of urea metabolism
   4. defects of copper metabolism
   5. LDL receptor defects
4. The Lesch-Nyhan syndrome is associated with a defect in the metabolism of:
   1. amino acids
   2. minerals
   3. glycogen
   4. purines
   5. pyridines
5. Match the following tests used to detect carriers of inborn errors with the disorder that they are designed to’ detect

hemoglobin electrophoresis hexosaminidase creatine kinase phenylalamine orotic acid Factor VIII assay \(\alpha\)-L-iduronidase

Tay-Sachs disease Duchenne muscular dystrophy Sickle cell anemia Hemophilia A Hurler’s syndrome

Use the following KEY to answer Questions 6-14:

1. 1, 2, and 3 are correct
2. 1 and 3 are correct
3. 2 and 4 are correct
4. only 4 is correct
5. all are correct

6. The basic premise(s) of the role of genes include the following:
   1. one structural gene encodes a polypeptide with a specific function
   2. one structural gene is paired with a regulatory one defining a structural protein
   3. a mutation of a structural gene results in a structurally altered polypeptide
   4. structural genes are limited in length to specific chromosomes
7. Testing for phenylketonuria and galactosemia is important because:
   1. the fetus can be terminated
   2. the fetus can be given enzymes to prevent defects
   3. the urinary excretion of amino acids and sugars can be reduced with consequent salvage of the kidney
   4. these diseases can be controlled by diet
8. Alpha-fetoprotein:
   1. is a plasma protein made by the fetal liver
   2. is virtually non-detectable in non-pregnant females
   3. if present in elevated amounts (2.5 times MOM) indicates fetal or pregnancy complications
   4. is present in equivalent amounts in maternal serum and amniotic fluid
9. Measurements of serum alpha-fetoprotein levels may be requested for:
   1. diagnosis of acute hepatitis
   2. screening for fetal neural tube defects
   3. diagnosis of spina bifida
   4. monitoring progress of certain cancers
10. Which of the following are considered inborn errors of metabolism:
    1. amino acidopathies
    2. organic acidurias
    3. glycogen storage diseases
    4. Wilson’s disease
11. A Structural gene locus can have a series of alleles. Which of the following are alleles?
    1. Duffey blood groups a and b
    2. hemoglobin A and hemoglobin S
    3. thalassemia
    4. hemoglobin A and C
12. Which of the following describe lysosomal storage diseases?
    1. recessively inherited disorders
    2. deficiency of specific acid hydrolases
    3. deficiency of hydrolases located within lysozomes
    4. autosomal dominant disorders
13. Inherited diseases can result in enzyme deficiencies. These can be the biochemical basis for a disease because of:
    1. lack of production of a product
    2. accumulation of substrate
    3. shunting of substrate to alternate pathway with production of a toxic compound
    4. urinary loss of metabolites
14. Inherited diseases of intermediary metabolism often produce:
    1. reduced serum levels of normal metabolites
    2. elevated urinary excretion of normal metabolites
    3. normal to lower excretion of normal metabolites
    4. urinary excretion of an abnormal metabolite

Answer

1. b (p. 910-912)
2. e (p. 911)
3. b (p. 926)
4. d (p. 931)
5.  
   1. b (p. 921)
   2. c (p. 912)
   3. a (p. 915, 932)
   4. f (p. 912, 934)
   5. g (p. 920-922)
6. b (p. 910)
7. d (p. 924)
8. a (p. 934)
9. c (p. 934)
10. e (p. 919-932)
11. a (p. 910)
12. a (p. 919)
13. a (p. 923)
14. c (p. 923)