Molecular Diagnosis In Three Inherited Retinal Disease Families Using Target Region Capture And High Through-put Sequencing

Introduction Inherited Retinal Disease(IRD), also called retinal degeneration or retinal dystrophy is characterized by impacted of visual field and other vision functions, which includes isolate retinal disease and syndromic retinal disease. RP is the leading cause of blindness in IRDs. An accurate and high throughput molecular diagnosis system is very significant in clinical diagnosis, due to highly clinical heterogeneity and genetic heterogeneity in IRD. The aim of this study was to identify the pathogenic mutations in three arIRD families using the targeted region capture base on high through-put sequencing.Methods A targeted region capture panel, which captured the exons of 283 genetic eye disease genes that included 165 known IRD disease-causing genes, was developed and applied to sequence the three probands who were firstly diagnosed with retinitis pigmentosa. Sequencing evaluation and comprehensive molecular diagnosis of these three patients were done, and the candidate pathogenic mutations were validated in families, respectively.Results As a result, over 350 folds sequencing depth and >92% of each targeted regions covered by at least 20 folds. These three patients were found to carry mutations in RDH5, CEP290 and NMNAT1 genes, respectively. It was inconsistent between molecular diagnosis and their initial clinical diagnosis. Then we revisited 2 of these 3 patients, and one was reclassified as fundus albipunctatus, another one was reclassified as RP with cataract.Conclusions We have identified mutations in disease-causing genes that were known to cause other IRDs instead of RP in these three arIRD families. Clinical revisited was performed and one of them was reclassified as fundus albipunctatus which is consistent with the molecular diagnosis. It suggested the significant and advancement of the target region capture methods base on high through-put sequencing in molecular diagnosis of genetic eye diseases, especially in the highly clinical heterogeneity and genetic heterogeneity diseases.