BS - Connective Tissue Diseases - Week 4

Question 1

Describe the three components of connective tissue structure.

Answer 1

Cells
ECM
-Fibre
-Ground substance

Question 2

Name the types of collagen that are fibrillar (5), fibril-associated (1), and sheet-like (1).

Answer 2

Fibrillar - I, II, III, V, XI
Fibril-associated - IX
Sheet-like - IV

Question 3

Which amino acid is particularly important for collagen and why?

Answer 3

Glycine because it is small and allows triple-helix packing

Question 4

What kind of helical structure does collagen have, and are its subunits identical?

Answer 4

Is a triple helix of 3 alpha subunits.
They can be identical or distinct:
Homotrimer - identical
Heterotrimer - 2 or 3 different subunits

Question 5

What 3 systems are most affected by CT disorders?

Answer 5

Musculoskeletal, ocular, and cardiovascular.

Question 6

Name 2 heritable CT disorders, and what structures they affect.

Answer 6

Stickler syndrome
-Vitreous changes
Marfan syndrome
-Ectopic lens

Question 7

Name an autoimmune CT disease that affects the sclera.

Answer 7

Scleritis, causing scleral necrosis

Question 8

Name a CT condition causing high myopia.

Answer 8

Scleral thinning

Question 9

Distinguish the numeral designation for collagen type and genes.

Answer 9

Type - Roman

Gene - Arabic

Question 10

A small change to which category of collagen would have the most profound effect?

Answer 10

Fibrillar

Question 11

What 3 things will an alteration in the amino acid content of a collagen fibre affect?

Answer 11

Structure
Stability
Biological performance

Question 12

Can changes to the ECM components of collagen affect collagen structure?

Answer 12

Yes, small heritable or environmentally driven changes can affect collagen structure, like lumican (type V)

Question 13

What effect does altering expression patterns of protein-associated macromolecules have on CT structure and/or function?

Answer 13

Loss of function

Question 14

Distinguish the following:
Autoimmunity
Hypersensitivity
Immune deficiency

Answer 14

Autoimmunity - failure to distinguish self from non-self
Hypersensitivity - excessive/inappropriate response
Immune deficiency - absent/inadequate response

Question 15

Describe Sjogren’s syndrome.

Answer 15

T-cell infiltration of the lacrimal gland

Question 16

Describe the genetic transmission of Stickler syndrome (2).

Answer 16

Autosomal dominant

Autosomal recessive

Question 17

What three collagen types are targetted by Stickler syndrom, and state its prevalence.

Answer 17

Type II, IX, and XI collagen

Prevalence - 1 : 7,500-9,000

Question 18

There are 5 subgroups of ocular and systemic manifestations of Stickler syndrome. Describe what each one is caused by, and whether it is ocular or systemic.

Answer 18

Type 1 - ocular and systemic
Type 2 - ocular and systemic
Type 3 - systemic only
Type 4 - ocular and systemic (recessive form)
Ocular only - like type 1, but no systemic manifestations

Question 19

Name 5 ocular manifestations of Stickler syndrome.

Answer 19

Vitreous abnormalities
Retinal degenerations/tears/breaks
Cataracts
Glaucoma (open angle)
High myopia

Question 20

Name 5 systemic manifestations of Stickler syndrome.

Answer 20

Skull, joint abnormalities
Hearing loss
cleft palate
Heart problems

Question 21

Name the ocular manifestations for type 1, 2, 3, and 4 forms of stickler syndrome.

Answer 21

Type 1 - sheet-like vitreous opacities or vitreous hypoplasia
Type 2 - beaded-string-like vitreous opacities or vitreous hypoplasia
Type 3 - no ocular phenotype
Type 4 (recessive) - premature vitreous degeneration

Question 22

Describe the genetic transmission of marfans syndrome and its penetrance.

Answer 22

Autosomal dominant with high penetrance

Question 23

Name the major ocular complication of marfans syndrome, and three conditions associated with it.

Answer 23

Ectopia lentis

• Flat cornea
• Increased axial length
• Hypoplastic iris or ciliary muscle, causing miosis

Question 24

Name an ocular manifestation of marfans syndrome and its cause.

Answer 24

Lens displacement - usually superiortemporally, caused by weakened lens zonules due to impaired fibrillin-1

Question 25

What is scleritis associated with?

Answer 25

An immune-mediated systemic inflammatory condition like rheumatoid arthritis or lupus

Question 26

Name 7 conditions associated with scleritis.

Answer 26

Thickened sclera
Intraocular sequelae
Retinal detachment
Glaucoma
Necrosis
Scleral perforation
Infection

Question 27

Name the four types of scleritis.

Answer 27

A - acute
B - nodular
C - necrotising with inflammation
D - necrotising without inflammation

Question 28

What condition does scleritis often coexist with?

Answer 28

Episcleritis

Question 29

Describe a symptom episcleritis. Is it associated with another condition like scleitis is?

Answer 29

Causes mild pain without discomfort

Not commonly associated with a systemic disease

Question 30

Does episcleritis resolve on its own?

Answer 30

Yes, within weeks

Question 31

Where is the sclera very thin in high myopic eyes?

Answer 31

Posterior pole

Question 32

Name four functional significances of high myopia.

Answer 32

Reduced tensile strength of the sclera
Major effect at the posterior pole
Causes increased rate of eye growth under normal IOP
Feature of young and myopic eyes