Mapping of Genes Involved in Inherited Eye Disorders

Abstract

The development and flmction of an organism is in large part controlled by genes. Mutations, a permanent change in the DNA sequence that makes up a gene, can lead to changes in the structure of an encoded protein or to a decrease or complete loss in its expression. Because a change in the DNA sequence affects all copies of the encoded protein, mutations can be particularly damaging to a cell or organism (Lodish et al., 2002). Mutations range in size from a single base to a large segment of a chromosome. Mutations that are passed from parent to child are called hereditary mutations or germ line mutations and can be responsible for inherited disorders. Recent advances in molecular genetics have made it possible to identify and isolate genes responsible for human diseases (Farber et at. , 1991). Genetic disorders are more common in consanguineous marriages because individuals born of consanguineous union have segments of their genomes that are homozygous as a result of inheriting identical ancestral genomic segments through both parents. One consequence of this is an increased incidence of recessive disease within these sibships (Woods etal. , 2006). Hereditary visual deficiencies can result from isolated or associated alterations of any structure of the eye. The identification of the molecular basis of ophthalmological disorders has revived interest in several conditions forgotten since their original description and allowed the development of specific therapeutic projects (Kaplan and Rozet, 2006).