Simple imaging technique could provide early diagnosis of a rare inherited neurodegenerative disorder

A cheap, non-invasive test could be key in diagnosing the rare inherited disease Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay (ARSACS), according to latest research. 

For the first time this test, that is used to diagnose many other eye diseases, has proven successful in achieving a definitive diagnosis in a very complex genetic neurodegenerative disorder.

The Optical Coherence Tomography (OCT) test is a readily available, non-invasive imaging technique which gives high-resolution images of the retina at the back of the eye. This is also the first time that a test that a non-laboratory-based genetic test has been shown to identify a genetic condition with accuracy.

The study which was led by Professor Paola Giunti, Head of the Ataxia Centre at UCL/UCLH, used OCT to test a large group of patients affected by ataxias to see if OCT could predict the genetics causing ataxia in some patients. To identify which genes were responsible, they screened several genes known to be responsible for some of the inherited ataxias.

The results showed that among the 300 individuals tested with OCT, significant retinal nerve fibre layer thickening was only identified in the 17 ARSACS patients. Patients with other causes of ataxia all had either a normal or thinned retinal nerve fibre layer. 

The study leads the way in providing evidence that deep phenotyping is needed in other neurodegenerative disorders to identify new biomarkers and specific diagnostic tools to diagnose genetic disorders with accuracy.

Professor Giunti, who is BRC-supported said: “We are excited now to extend our study to try and understand the nature of this retinal thickening by further basic research that we are hoping to carry out in my laboratory.”

ARSACS is a progressive neurodegenerative condition and a type of ataxia, which is most prevalent in a region of Quebec, Canada. ARSACS affects approximately 1 in 1500 to 2000 individuals. Outside of Quebec it is rare and the prevalence is unknown. People of any age may be affected by ARSACS. The condition is an autosomal recessive disorder; affected individuals have inherited two faulty genes, one from each parent. It is possible to inherit a single faulty copy of the gene without developing the condition. There is currently no cure or treatment to stop ARSACS’s progression.

To read the full paper please see the Brain journal.