Research into a disease that is rare – affecting less than five out of every 10,000 people – might mistakenly be thought of as only useful in very specific circumstances.

However, the potential impact of rare disease research can be far broader.

Researchers at CERA are investigating several rare diseases that affect vision, including Leber’s Hereditary Optic Neuropathy (LHON), retinitis pigmentosa (RP) and Usher syndrome.

Discoveries made have the potential to not just treat the conditions being studied, but also improve how more common diseases are understood.

Inherited Retinal Diseases

While individually rare, when grouped together Inherited Retinal Diseases (IRD) are the most common cause of blindness among working-age Australians.

They include a wide range of conditions including retinitis pigmentosa, Stargardt’s disease and many more, and all are caused by a ‘mistake’ in one or more genes that leads to vision loss.

“Being diagnosed with a rare disease is challenging for so many reasons,” says Associate Professor Lauren Ayton, Principal Research Fellow, CERA Retinal Gene Therapy Unit.

“As well as trying to find the best treatments, people often have to educate the health care professionals that they seek care from.

“That’s why our team are passionate about translating our research into clinician education, so our healthcare system is ready for the emerging treatments on the horizon.”

Associate Professor Ayton is one of the leaders of the VENTURE Study – a large project aiming to improve understanding of IRDs, how they progress and the impact of living with the disease.

Looking at many different diseases, the project aims to better understand how people with IRDs and their families can be supported to make informed choices about genetic testing, trial participation and treatment.

“One of the fantastic things about clinical research is it is often transferrable,” says Associate Professor Ayton.

“So, even though we might be developing a treatment for a very specific and rare eye disease, the methods we develop to make the treatment, deliver the treatment, and measure the outcomes can be used in many different applications.”

LHON learning

Leber’s hereditary optic neuropathy (LHON) – a rare disease that damages the optic nerve and can cause the loss of central vision – might also reveal more about other conditions.

LHON mutations affect primarily three of the 13 genes found in the DNA of mitochondria – a structure within cells that provides energy.

“In some people with LHON, having this mutation causes mitochondria to work less efficiently, which is enough to trigger retinal ganglion cells to eventually die and for the person to lose vision,” says Dr Isabel Lopez Sanchez, Head of Mitochondrial Biology and Disease at CERA.

One mystery Dr Lopez Sanchez is investigating is why not everyone with a LHON mutation loses vision.

As well as a potential treatment for LHON, this might also reveal information about other diseases.

“Understanding how this one change in the mitochondrial genome that causes a little bit of dysfunction in mitochondria, then leads on to vision loss, may help us understand what happens in other diseases that also affect retinal ganglion cells like glaucoma,” says Lopez Sanchez.

Usher Syndrome

New ways to treat rare diseases also have the potential to improve treatments for many other conditions.

Retinitis pigmentosa – an IRD that affects the photoreceptor cells in the retina – is associated with Usher syndrome, a condition that affects vision and hearing, and can also cause balance problems.

Dr Sandy Hung, Research Fellow in Clinical Genetics Unit, is currently investigating improved ways to deliver gene therapies that have the potential to treat the condition, but it may also have more uses.

“Our current target is photoreceptor cells, but in the future, we might be able to branch off and target retinal ganglion cells, or maybe even other cells of the body,” says Dr Hung.

Research into all of these conditions is working towards preventing vision loss for people with these rare conditions, but also potentially many more.