The Molecular, Biochemical, and Cellular Basis of Genetic Disease Part III

Question 1

What is type 1 procollagen composed of?

Answer 1

two proa1 chains and one proa2 chains

Question 2

In what direction does the assembly of pro-a chains occur?

Answer 2

carboxy terminus to amino termus

Question 3

What type of mutations in chains in type 1 collagen cause OI?

Answer 3

null mutations and missense glycine substitution mutations

Question 4

When are the phenotypic effects of OI most severe?

Answer 4

when the glycine substitutions are near the C-terminus of the chain, if the substituted amino acis residue is charged, or if the amino acid substituted is bulkier than glycine

Question 5

What is the cofactor protein of gamma-secretase?

Answer 5

presenilin 1

Question 6

What is the major difference in PSEN1 and PSEN 2 mutations

Answer 6

age of onset:
PSEN1 - 35-60
PSEN2- 40-85

Question 7

What is the effect of the E2 on AD?

Answer 7

protective

Question 8

What do mitochondrial DNA disease result from?

Answer 8

defects of single genes on the mitochondrial DNA

Question 9

Name three mitochondrial diseases

Answer 9

Leber’s
MELAS
MERRF

Question 10

What is mitochondrial myopathy characterized by?

Answer 10

ragged red muscle fibers

Question 11

What is heteroplasmy?

Answer 11

it leads to an unpredictable and variable fraction of mutant mtDNA bein present in any particular tissue, and undoubtedly accounts for much of the pleiotropy and variable expression.

Question 12

a pattern of inheritance in which individuals in the most recent generations of the pedigree develop the disease at an earlier age and/or with greater severity as it is transmitted through a family

Answer 12

anticipation

Question 13

Which Class of unstable repeat expansions is this?:
Diseases due to the expansion of noncoding repeats that can cause a loss of protein function. Impaired transcription of pre-mRNA from the affected gene seen with fragile X syndrome and Freidreich ataxia

Answer 13

Class 1

Question 14

Which Class of unstable repeat expansions is this?:
Disorders resulting from expansions of noncoding repeats that confer novel properties on the RNA, ex: Myotonic Dystrophy, Fragile X-associated tremor/ataxia syndrome

Answer 14

Class 2

Question 15

Which Class of unstable repeat expansions is this?:

Diseases due to repeat expansion of a codon, ex: CAG for glutamine in Huntington disease

Answer 15

Class 3