Genetics of ARIRD Quiz

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Questions and Answers

What percentage of autosomal dominant (AD) rod-cone dystrophies is attributed to Rho-related retinitis pigmentosa?

40-50%

10-15%

30-40%

20-30% (correct)

What is the primary function of rhodopsin, which is encoded by the Rho gene?

Rod cell apoptosis

Phototransduction initiation (correct)

Color vision maintenance

Cone cell regeneration

How do autosomal dominant (AD) inherited retinal diseases compare to autosomal recessive (AR) diseases?

AD diseases have no genetic basis

AD diseases are more frequent and more severe

AD diseases are less frequent and less severe (correct)

AD diseases exclusively affect cone cells

Which type of inherited retinal disease tends to be less frequent and less severe?

Autosomal dominant diseases Signup and view all the answers

Which of the following is true regarding autosomal recessive inherited retinal dystrophies?

They are more common than AD diseases Signup and view all the answers

What role does arrestin play in the functioning of rhodopsin?

It prevents activated rhodopsin from binding to transducin. Signup and view all the answers

How does retinitis pigmentosa lead to vision loss?

Through degeneration of photoreceptor cells, specifically rods and cones. Signup and view all the answers

What causes tunnel vision in individuals with retinitis pigmentosa?

Loss of function primarily in peripheral photoreceptor cells. Signup and view all the answers

In retinitis pigmentosa, which genetic defect is commonly involved?

Defect in rhodopsin or proteins involved in phototransduction. Signup and view all the answers

What type of genetic inheritance pattern is most commonly associated with retinitis pigmentosa?

Autosomal recessive. Signup and view all the answers

What is required for a child to be affected by ARIRD?

Both parents must be carriers of a gene variant in the same gene. Signup and view all the answers

In the context of gene inheritance, what role do carriers play in conditions like ARIRD?

Carriers can pass the gene variant without being affected. Signup and view all the answers

Which of the following best describes autosomal recessive inheritance?

A trait expressed only when both parents carry a recessive gene variant. Signup and view all the answers

What impact do ABCA4 mutations have on vision?

They can cause degeneration of photoreceptors. Signup and view all the answers

What is the significance of gene variants in ARIRD?

They can cause a spectrum of visual impairments depending on the variant. Signup and view all the answers

Study Notes

Autosomal Recessive Inherited Retinal Dystrophy (ARIRD)

ARIRD requires both parents to be carriers of a gene variant in the same gene for a child to be affected.
Rho-related retinitis pigmentosa is a type of rod-cone dystrophy linked to the rhodopsin gene, which encodes for the protein rhodopsin.
Accounts for 20-30% of autosomal dominant (AD) rod-cone dystrophies.
AD inherited retinal diseases are less common and usually less severe than autosomal recessive (AR) and X-linked diseases.

Rhodopsin Activation and Regulation

Activated rhodopsin is quickly phosphorylated by rhodopsin kinase, which is crucial for its regulation.
Phosphorylated rhodopsin binds to arrestin, preventing further activation by transducin and thereby modulating the phototransduction pathway.

Retinitis Pigmentosa

Retinitis pigmentosa is a genetic disorder characterized by tunnel vision.
Results from genetic defects in rhodopsin or other proteins essential for phototransduction.
Involves degeneration of the retina and leads to photoreceptor cell loss, particularly affecting rods and cones.
Progressive vision loss occurs as photoreceptor cells degenerate over time.

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Description

Test your knowledge on Autosomal Recessive Inherited Retinal Dystrophy (ARIRD) and how it affects inheritance patterns. Understand the role of gene variants and the importance of both parents being carriers for a child to be affected. This quiz is essential for those studying genetics and hereditary conditions.