Clinical and Genetic Evaluation of a Cohort of Pediatric Patients with Severe Inherited Retinal Dystrophies
Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania Luigi Vanvitelli, via Pansini 5, Naples 80131, Italy
Medical Genetics, Department of Biochemistry, Biophysics and General Pathology, Università degli Studi della Campania Luigi Vanvitelli, via Luigi De Crecchio 7, Naples 80138, Italy
Telethon Institute of Genetics and Medicine, via Campi Flegrei 34, Pozzuoli 80078, Italy
Authors to whom correspondence should be addressed.
These authors contributed equally to this work.
Genes 2017, 8(10), 280; https://0-doi-org.brum.beds.ac.uk/10.3390/genes8100280
Received: 29 June 2017 / Revised: 2 October 2017 / Accepted: 13 October 2017 / Published: 20 October 2017
(This article belongs to the Special Issue Inherited Retinal Disease: Novel Candidate Genes, Genotype–Phenotype Correlations and Inheritance Models)
We performed a clinical and genetic characterization of a pediatric cohort of patients with inherited retinal dystrophy (IRD) to identify the most suitable cases for gene therapy. The cohort comprised 43 patients, aged between 2 and 18 years, with severe isolated IRD at the time of presentation. The ophthalmological characterization also included assessment of the photoreceptor layer integrity in the macular region (ellipsoid zone (EZ) band). In parallel, we carried out a targeted, next-generation sequencing (NGS)-based analysis using a panel that covers over 150 genes with either an established or a candidate role in IRD pathogenesis. Based on the ophthalmological assessment, the cohort was composed of 24 Leber congenital amaurosis, 14 early onset retinitis pigmentosa, and 5 achromatopsia patients. We identified causative mutations in 58.1% of the cases. We also found novel genotype-phenotype correlations in patients harboring mutations in the CEP290 and CNGB3 genes. The EZ band was detectable in 40% of the analyzed cases, also in patients with genotypes usually associated with severe clinical manifestations. This study provides the first detailed clinical-genetic assessment of severe IRDs with infantile onset and lays the foundation of a standardized protocol for the selection of patients that are more likely to benefit from gene replacement therapeutic approaches.