Genetic Background of Macular Telangiectasia Type 2.

Macular telangiectasia type 2 (MacTel) is a slowly progressive macular disorder that is often diagnosed late due to the gradual onset of vision loss. Recent advances in diagnostic techniques have facilitated earlier detection and have shown that MacTel is more common than initially thought. The disease is genetically complex, and multiple variants contribute incrementally to the overall risk. The familial occurrence of the disease prompted the investigation of the genetic background of MacTel. To better understand the molecular milieu of the disease, a literature review of the clinical reports and publications investigating the genetic factors of MacTel was performed. To date, disease-associated variants have been found in genes involved in amino acid (glycine/serine) metabolism and transport, urea cycle, lipid metabolism, and retinal vasculature and thickness. Variants in genes implicated in sphingolipid metabolism and fatty acid/steroid/retinol metabolism have been found in patients with neurological disorders who also have MacTel. Retinal metabolism involves complex biochemical processes that are essential for maintaining the high energy requirements of the retina. Genetic alterations can disrupt key metabolic pathways, leading to retinal cell degradation and the subsequent vision loss that characterizes several retinal disorders, including MacTel. This review article summarizes genetic findings that may allow MacTel to be further investigated as an inherited retinal disorder.