Epidemiology, signs and symptoms of Inherited Retinal Dystrophies

Question 1

What are the different main retinal dystrophies?

Answer 1

~ Retinitis pigmentosa
~ Cone/Rod dystrophy
~ Congenital stationary night blindness
~ Stargardt’s disease
~ Best’s vitelliform dystrophy

Question 2

What is a genotype?

Answer 2

~ Your genetic classification
~ e.g. you have a mutated gene that codes for a protein that leads to a disease

Question 3

What is a phenotype?

Answer 3

~ Physical appearance
~ e.g. you actually show the disease
* Whether this happens or not depends upon the mode of inheritance (dominant or recessive) and the penetrance

Question 4

What is X-linked?

Answer 4

~ The gene is coded on the X chromosome
~ Females have 2, males have 1

Question 5

What is autosomal?

Answer 5

~ The gene is coded on one of the 22 non-sex chromosomes
~ You get one of these from your mother and one of these from your father

Question 6

What is dominant?

Answer 6

~ In order to show the phenotype you only require 1 mutated gene

Question 7

What is recessive?

Answer 7

~ In order to show the phenotype you require 2 copies of the mutated gene

Question 8

What is penetrance?

Answer 8

~ Even if you have the genotype you may not get a severe form of the disease