Phenotype variations of retinal dystrophies caused by mutations in the <scp>RLBP</scp>1 gene

• Published in: Acta Ophthalmologica
• Main Authors: Hipp, Stephanie, Zobor, Gergely, Glöckle, Nicola, Mohr, Julia, Kohl, Susanne, Zrenner, Eberhart, Weisschuh, Nicole, Zobor, Ditta
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2014
• Subjects: Ophthalmology; General Medicine; Newfoundland
• Online Access: http://dx.doi.org/10.1111/aos.12573; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Faos.12573; https://onlinelibrary.wiley.com/doi/pdf/10.1111/aos.12573

Abstract Purpose Mutations in the RLBP 1 gene encoding the cellular retinaldehyde‐binding protein ( CRALBP ) cause autosomal recessive progressive retinopathy, such as retinitis punctata albescens ( RPA ), Bothnia‐type dystrophy ( BD ), Newfoundland rod‐cone dystrophy ( NFRCD ), retinitis pigmentosa ( RP ) and fundus albipunctatus ( FA ). We present the clinical heterogeneity and genetic findings of seven patients from five families with RLBP 1 mutations, including three novel mutations. Methods Seven patients underwent complete ophthalmological examination including psychophysical tests (visual acuity, colour vision, visual field, dark adaptation) and electrophysiology (Ganzfeld and multifocal ERG ). Additionally, fundus photography, autofluorescence ( FAF ) and spectral domain optical coherence tomography ( OCT ) recordings were performed. Genomic DNA was analysed by high‐throughput sequencing for all RP ‐related genes in a diagnostic set‐up. Results The patients presented with variable phenotypes, including RPA , BD , RP and a mild form of NFRCD . No detectable or severely depressed responses in electrophysiological examinations were seen in all cases. Visual field constriction was variable among individuals. Severely reduced visual acuity was only observed in the patient presenting with BD . The other patients retained mild to moderate reduction of visual function. Despite the morphological differences, central retinal thinning – as a common feature – could be observed. Conclusions The fact that different mutations in RLBP 1 are correlated with quite different morphological and functional characteristics outlines the complexity of the protein. Identifying new mutations and comparing the different phenotypes may help to better understand the function of the protein and the consequences in pathological changes that involve RPE and choroid.