The genetics of the corneal dystrophies.

Several comprehensive reviews have been written recently that summarize what is currently known about the molecular genetic basis of the corneal dystrophies. The one that is the current definitive reference on the subject is the IC3D classification of the corneal dystrophies, written by an international group of experts on the corneal dystrophies. In this work, each gene in which a pathogenic mutation has been identified in a patient with a corneal dystrophy is listed and an appendix is provided with a complete list of the genes and the mutations listed at the nucleotide and amino acid levels (with references). As the IC3D classification of the corneal dystrophies is readily available to the reader both in print and online, this chapter will not focus on reviewing the genes and mutations that have been associated with the corneal dystrophies. Instead, it will provide an overview of the genetics of the corneal dystrophies, discussing first the clinical and genetic spectrum of the corneal dystrophies and then the limitations of a genetically based classification system for the corneal dystrophies. The last section of this chapter will discuss how the discovery of mutations that cause the corneal dystrophies is not the end of the process of scientific discovery, but only the beginning, as vision scientists attempt to determine how the identified mutations lead to the formation of corneal deposits or loss of endothelial function, and develop strategies to modulate gene expression.