Fiorentino Alessia, Yu Jing, Arno Gavin, Pontikos Nikolas, Halford Stephanie, Broadgate Suzanne, Michaelides Michel, Carss Keren J, Raymond F Lucy, Cheetham Michael E, Webster Andrew R, Downes Susan M, Hardcastle Alison J
UCL Institute of Ophthalmology, London, UK.
Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK.
Mol Vis. 2018 Aug 31;24:603-612. eCollection 2018.
Mutations in encoding ADP-ribosylation factor-like 2 binding protein, have recently been implicated as a cause of autosomal recessive retinitis pigmentosa (arRP), with three homozygous variants identified to date. In this study, we performed next-generation sequencing to reveal additional arRP cases associated with variants.
Whole-genome sequencing (WGS) or whole-exome sequencing (WES) was performed in 1,051 unrelated individuals recruited for the UK Inherited Retinal Disease Consortium and NIHR-BioResource Rare Diseases research studies. Sanger sequencing was used to validate the next-generation sequencing data, and reverse transcriptase (RT)-PCR analysis was performed on RNA extracted from blood from affected individuals to test for altered splicing of . Detailed phenotyping was performed, including clinical evaluation, electroretinography, fundus photography, fundus autofluorescence imaging, and spectral-domain optical coherence tomography.
Homozygous variants in (NM_012106.3) were identified in two unrelated individuals with RP. The variants, c.207+1G>A and c.390+5G>A, at conserved splice donor sites for intron 3 and intron 5, respectively, were predicted to alter the pre-mRNA splicing of . RT-PCR spanning the affected introns revealed that both variants caused abnormal splicing of in samples from affected individuals.
This study identified two homozygous variants in as a rare cause of arRP. Further studies are required to define the underlying disease mechanism causing retinal degeneration as a result of mutations in and any phenotype-genotype correlation associated with residual levels of the wild-type transcript.
编码ADP核糖基化因子样2结合蛋白的基因突变最近被认为是常染色体隐性视网膜色素变性（arRP）的一个病因，迄今为止已鉴定出三种纯合变体。在本研究中，我们进行了二代测序以揭示与该变体相关的其他arRP病例。
对为英国遗传性视网膜疾病联盟和NIHR生物资源罕见病研究招募的1051名无亲缘关系的个体进行全基因组测序（WGS）或全外显子组测序（WES）。使用桑格测序法验证二代测序数据，并对从患病个体血液中提取的RNA进行逆转录酶（RT）-PCR分析，以检测该基因的剪接变化。进行了详细的表型分析，包括临床评估、视网膜电图、眼底照相、眼底自发荧光成像和光谱域光学相干断层扫描。
在两名无亲缘关系的视网膜色素变性患者中鉴定出该基因（NM_012106.3）的纯合变体。这两个变体分别为c.207+1G>A和c.390+5G>A，分别位于第3内含子和第5内含子保守的剪接供体位点，预计会改变该基因的前体mRNA剪接。跨越受影响内含子的RT-PCR显示，这两个变体均导致患病个体样本中该基因的异常剪接。
本研究鉴定出该基因的两个纯合变体是arRP的罕见病因。需要进一步研究来确定该基因突变导致视网膜变性的潜在疾病机制，以及与野生型转录本残留水平相关的任何表型-基因型相关性。
