Molecular Genetics and Clinical Aspects of Macular Corneal Dystrophy

Abstract

The prevalence of macular corneal dystrophy (MCD) varies immensely in different parts of the world. Though MCD is rare corneal dystrophy, consanguinity among the populations increases the risk of occurrence. It is most predominant in Iceland, Saudi Arabia, and South India due to high degree of consanguinity. Unlike in the Western countries, MCD is the most common corneal stromal dystrophy in India. MCD is an inherited, autosomal recessive disorder caused by defective keratan sulfate (KS) metabolism. It is characterized by bilateral, progressive clouding of the corneal stroma with the presence of grayish-white, ill-defined opacities. The clinical manifestations of MCD usually start in the first decade of life leading to progressive visual loss eventually necessitating corneal transplantation by the fifth decade of life. So far, there are limited studies in MCD for understanding the relationship between the mutations in CHST6 and the mechanism of unsulfated KS deposits. Therefore, understanding the genetic, clinical, and pathophysiological aspects of this complex disease is very essential for the newer treatment options like gene therapies. This chapter provides detailed insight into epidemiology, biochemical mechanism, immunophenotypes, genetics, and clinical aspects of MCD, which enriches our understanding for future research purposes.