Cloning and Functional Studies of LCA9 Disease Gene

Abstract

Purpose: : Leber Congenital Amaurosis (LCA) represents the most severe form of human inherited retinal dystrophies with photoreceptor neuron degeneration and blindness with an incidence of ~1 in 80,000. Recently, we have cloned a novel disease gene at the LCA9 locus. The goal of this study is to understand the function of the LCA9 gene.

Methods: : Whole exome sequencing approach is used to sequence a collection of LCA patients. Immuno-histochemistry (IHC) is used to characterize the expression profile of LCA9 in both developing and mature retina in mice. Both biochemistry and cell culture method is used to assess the impact of the human mutations identified in our study to protein function.

Results: : Using exome sequencing combined with candidate gene screen, we have identified a total of seven human LCA patient families carrying mutations in LCA9. Antibody staining of the developing and mature mice retina indicates that LCA9 is highly expressed in the photoreceptor cells. Follow up functional assays of the mutations identified in our study indicated that these mutations impair the enzymatic activity and/or protein localization.

Conclusions: : We have cloned the elusive LCA9 disease gene. Detailed functional studies of this gene will likely to provide important insight to human retinal disease.

Keywords: retinal degenerations: hereditary • genetics • gene mapping