Focused on Retinitis Pigmentosa (RP)

Retinitis Pigmentosa (RP) refers to a group of retinal dystrophies that cause progressive degeneration of the retina.

Retinitis Pigmentosa (RP) refers to a group of retinal dystrophies that cause progressive degeneration of the retina.

Around one in 3,000 children are born with RP, and the condition can strike any family, even one with no known history of the disease.

The retina, located at the back of the eye, is made up of millions of light-sensitive ‘photoreceptor cells’ which transmit electrical impulses to the brain, thus enabling sight.

RP involves the degeneration of these photoreceptors over time.

Typical symptoms include “night blindness” and “tunnel vision”. Cataracts are also a common complication.

RP sufferers have no common age of onset of symptoms and no uniform rate and extent of vision loss. These can vary markedly from individual to individual and are not usually able to be predicted. There is currently no cure for RP.

Exome Sequencing: Finding Answers for Families

Associate Professor Robyn Jamieson is researching the underlying genetic causes of inherited eye diseases such as retinitis pigmentosa.

Associate Professor Robyn Jamieson is researching the underlying genetic causes of inherited eye diseases such as retinitis pigmentosa.

“There are recent striking technological advances in our capacity to examine all of the genes in a person” says Assoc.Prof. Jamieson “and ‘exome sequencing’ is one of the most exciting avenues now available.”

Each of us has around three billion dot points (called bases) in our cells that contribute to our genetic makeup. Around 45 million of these bases are found in the coding regions (exons) of our 23,000 genes, and there are on average at least 10 exons per gene.

“Exome Sequencing” allows us to look at most of the key bases in just one test, rather than having to sequence each of the exons individually with 230,000 separate tests!

“We are now using this more accessible technique to discover the underlying disease genes which cause inherited eye diseases” says Assoc Prof Jamieson.

“We are collaborating with a number of international sequencing centres and, most excitingly, have already made molecular diagnoses in patients where this was previously not possible.”

Further illustrating the international importance of this work, Assoc. Prof. Jamieson was invited to present at the Human Genome Organisation International Meeting in 2012.

The identification of disease genes offers direct diagnostic benefits to patients, and is especially critical for the development of new treatment strategies such as gene therapy.

“Gene therapy is an emerging technique” says Robyn “that uses genes to treat or prevent disease. Still experimental, it offers much potential for doctors to treat a disorder by inserting a healthy copy of the gene into the eye instead of using drugs or surgery.”