Macular Dystrophies

Question 1

What is the most common type of Stargardt disease?

Answer 1

• juvenile-onset macular dystrophy

Question 2

What is the typical rate of progression for Stargardt?

Answer 2

• rapid onset vision loss (20/20 -> 20/200) in months
• usually stablizes around 20/200

Question 3

What is the characteristic physical feature of Stargardt?

Answer 3

“pisciform” flecks in the retina (they look like bright spots)

Question 4

Stargardt
* gene
* inheritance

Answer 4

• gene = ABCA4
• inheritance = AR

Question 5

Many retinal dystrophies are due to a variant in ABCA4. Which is considered the most severe condition?

Answer 5

CORD

Question 6

Mechanism for ABCA4-opathies

Answer 6

• shuttling waste
• dysfunction -> accumulation of lipofuscin (flecks on images)
• this is an accumulation of vitamin A which can’t be used b/c all clumped

Question 7

What is one recommendaiton that we can give for people with ABCA4-opathies?

Answer 7

avoid excess vitamin A

Question 8

PRPH2
* age of onset
* inheritance
* disease category

Answer 8

• adult
• AD
• macular disease

Question 9

CORD can be AR, AD, or XL
Name one gene for each

Answer 9

• AR: ABCA4
• AD: GUCA1A
• XLr: RPGR ORF15

Question 10

Best disease
* type of dystrophy
* characteristic lesion
* primary affected tissue

Answer 10

• rare macular dystrophy
• “vitelliform” lesion of lipofuscin in macula (looks like egg yolk)
• retinal pigmented epithelium (RPE)

Question 11

General trend of ERG findings for macular diseases

Answer 11

• full field ERG = normal
• multifocal ERG = abnormal

Question 12

What unique test can be useful for Best disease?

Answer 12

EOG (electro-oculogram which measures RPE function

Question 13

Best disease
* inheritance pattern
* gene

eggs are best.

Answer 13

• AD but homozygotes have more severe dx with earlier onset
• BEST1 (VMD2)

variable expressivity and reduced penetrance

Question 14

What is the main concern regarding management of pateints with Best disease?

Answer 14

• risk for choroidal neovascularization which means increased risk for bleeding which can lead to unnecessary vision loss b/c there are treatment options
• laser and anti-VEGF reduce risk for bleeds

Question 15

macular disease are NOT

Answer 15

photoreceptor disease