Question

Which of these is a genetic defect related to the eye?

• A. Colour blindness
• B. Usher's syndrome
• C. Pallister W syndrome
• D. Alopecia

Answer 1

The correct option is A

Colour blindness

The correct option is option A.

The explanation for the correct option:

1. Colour blindness is a hereditary condition.
2. It is passed down from our parents.
3. The common colour blindness is red and green.
4. This is a defect in the 23rd chromosome in females.
5. The 'gene' for colour blindness is found on one of the X chromosomes.
6. The woman is a carrier where one X-chromosome is defective.
7. The male is all time affected as they have on X-chromosome.

The explanation for the incorrect options:

Option B:

1. Usher syndrome, also known as Hallgren syndrome.
2. It is a rare genetic disorder caused by a mutation in one of at least 11 genes.
3. This results in hearing loss and visual impairment.
4. Mutations in genes are involved in the function of the inner ear and retina.
5. These mutations are passed down in an autosomal recessive manner.

Option C:

1. Pallister W syndrome is a rare genetic disorder.
2. It is characterised by unusual facial features such as the palate and upper lip clefting.
3. Other symptoms may include mental retardation, speech difficulties, and arm and leg bone deformities.
4. Pallister W syndrome's exact cause is unknown.

Option D:

1. Alopecia areata is a condition that causes patches of hair loss.
2. These patches may connect and become more visible as a result.
3. The condition occurs when your immune system attacks your hair follicles, resulting in hair loss.
4. It can affect people of any race, gender, or age.

Final answer: Colour blindness is a genetic defect related to the eye.