LG3.10 Genetics of Connective Tissue Disorders – Dr. Olson

Question 1

What is allelic heterogeneity?

Answer 1

One phenotype produced by different mutations at the same locus.

Question 2

What is an example of allelic heterogeneity?

Answer 2

Cystic fibrosis

Question 3

What is locus heterogeneity?

Answer 3

One phenotype produced by different mutations at different loci.

Question 4

What is heterogeneity?

Answer 4

Is a phenomenon in which a single phenotype or genetic disorder may be caused by any one of a multiple number of alleles or non-allele.

Question 5

What is a dominant negative mutation?

Answer 5

Abnormal function that interferes with nomad allele

Question 6

What is pleitoropy?

Answer 6

Occurs when one gene influences multiple, seemingly unrelated phenotypic traits, an example being phenylketonuria, which is a human disease that affects multiple systems but is caused by one gene defect.

Question 7

What is collagen made by?

Answer 7

Fibroblasts.

Question 8

What is Ehlers-Danlos syndrome?

Answer 8

• Class of 10 disorders with joint flexibility problems
• Loose joints
• Strechy skin

Question 9

What is Epidermolysis Bullosa?

Answer 9

-Skin blisters and tearing

Question 10

What are the three types of Epidermolysis Bullosa?

Answer 10

• EB simplex
• Junctional EB
• Dystrophic EB

Question 11

What is EB simplex?

Answer 11

Autosomal dominant, keratin mutation

Question 12

What is junctional EB?

Answer 12

Autosomal recessive, laminin and collagen in basement membrane of epithelia.

Question 13

What is Dystrophic EB?

Answer 13

COL7A1, dominant and recessive

Question 14

What is Marfan syndrome?

Answer 14

• Long, tall, fragile

- Fibrillin

Question 15

What gene is suspected in Marfan syndrome?

Answer 15

FBN1 gene is also part of a cell signaling pathway, increasing TGF-B signaling

Question 16

What is the major issue caused by Marfan syndrome?

Answer 16

Weakened heart, valves, lungs, and aorta.

Question 17

What is osteogenesis imperfecta?

Answer 17

-Brittle bone disease

Question 18

What type of mutation normally occurs in osteogenesis imperfect?

Answer 18

Type 1 collagen mutation

Question 19

What specific location of a coding sequence on a chromosome is known as a?
A) An allele
B) A locus
C) A chiasma
D) A genotype
E) A phenotype

Answer 19

A) A locus

Question 20

I am a carrier of an autosomal recessive disease, like Tay’Sach’s, but am otherwise normal. As a carrier I do not have the disease, but carry an allele that may give it to my offspring. Am I wild Type?

Answer 20

YES!

Question 21

A patient with a muscular dystrophy is producing a dystrophin gene product that is missing 35 amino acids on its carboxyl end? Which mutation is the set candidate?

Answer 21

Nonsense Mutation