Neurology Central

Genetic analysis identifies loci associated with macular telangiectasia type 2


An international collaboration of researchers has identified five loci in the genome that could be responsible for the development of macular telangiectasia type 2 (MacTel), an incurable and untreatable degenerative eye disease that leads to blindness. The report was published in Nature Genetics and led by investigators from the Walter and Eliza Hall Institute of Medical Research (Melbourne, Australia).

MacTel is a rare retinal disease, which mainly affects people over the age of 40. It is characterized by abnormal growth of blood vessels in the macula; sufferers experience a loss of central vision, which is essential for tasks that require focus such as driving or reading.

In this study, genome-wide association studies were used to perform a genetic analysis of MacTel patients from around the world. By collaborating with researchers from London (UK) and New York (USA), the genetics of 476 people with MacTel were analyzed, along with 1733 controls.

Melanie Bahlo (Walter and Eliza Hall Institute of Medical Research), one of the senior investigators, discussed the study findings: “We analyzed more than 6 million genetic markers and identified five regions, called loci, across the genome that had similar patterns in people with the disease, but not the healthy individuals. These five genetic risk loci are our treasure map, telling us where to ‘keep digging’ in order to discover the specific genes implicated in MacTel.”

In addition, the genetic analysis also revealed that people with the MacTel genetic risk loci also had abnormal levels of glycine and serine, leading to changes in their metabolism. This could mean that there is an association between the levels of these two amino acids and the onset of MacTel. Bahlo explained: “Though the exact link between the disease and glycine and serine is yet to be confirmed, the connection is an exciting clue to help us further explore metabolic abnormalities in people with MacTel.”

The team now hopes that these findings will help them develop strategies for preventing and treating MacTel. Thomas Scerri (Walter and Eliza Hall Institute of Medical Research), another of the study authors, commented: “We are continuing to explore the genetic data to try to identify the specific genes involved, and the precise genetic variations that are leading to the disease.”

Sources: Scerri TS, Quaglieri A, Cai C et al. Genome-wide analyses identify common variants associated with macular telangiectasia type 2. Nat. Genet. doi:10.1038/ng.3799 (2017) (Epub ahead of print);