Jules Stein Eye Institute, University of California Los Angeles, 200 Stein Plaza, Los Angeles, CA 90095, USA.
BMC Med Genet. 2012 Aug 3;13:67. doi: 10.1186/1471-2350-13-67.
The commonest genetic form of juvenile or early adult onset macular degeneration is Stargardt Disease (STGD) caused by recessive mutations in the gene ABCA4. However, high phenotypic and allelic heterogeneity and a small but non-trivial amount of locus heterogeneity currently impede conclusive molecular diagnosis in a significant proportion of cases.
We performed whole exome sequencing (WES) of nine putative Stargardt Disease probands and searched for potentially disease-causing genetic variants in previously identified retinal or macular dystrophy genes. Follow-up dideoxy sequencing was performed for confirmation and to screen for mutations in an additional set of affected individuals lacking a definitive molecular diagnosis.
Whole exome sequencing revealed seven likely disease-causing variants across four genes, providing a confident genetic diagnosis in six previously uncharacterized participants. We identified four previously missed mutations in ABCA4 across three individuals. Likely disease-causing mutations in RDS/PRPH2, ELOVL, and CRB1 were also identified.
Our findings highlight the enormous potential of whole exome sequencing in Stargardt Disease molecular diagnosis and research. WES adequately assayed all coding sequences and canonical splice sites of ABCA4 in this study. Additionally, WES enables the identification of disease-related alleles in other genes. This work highlights the importance of collecting parental genetic material for WES testing as the current knowledge of human genome variation limits the determination of causality between identified variants and disease. While larger sample sizes are required to establish the precision and accuracy of this type of testing, this study supports WES for inherited early onset macular degeneration disorders as an alternative to standard mutation screening techniques.
最常见的青少年或成年早期发病的黄斑变性的遗传形式是由 ABCA4 基因的隐性突变引起的斯塔加特病（STGD）。然而，目前表型和等位基因高度异质性，以及小但并非微不足道的基因座异质性，在很大一部分病例中阻碍了明确的分子诊断。
我们对 9 名疑似斯塔加特病患者进行了全外显子组测序（WES），并在先前确定的视网膜或黄斑变性基因中寻找可能导致疾病的遗传变异。进行双脱氧测序以进行确认，并对一组缺乏明确分子诊断的额外受影响个体进行突变筛查。
全外显子组测序揭示了四个基因中的七个可能的致病变异，为六个以前未表征的参与者提供了明确的遗传诊断。我们在三个个体中发现了 ABCA4 中四个先前遗漏的突变。还鉴定了 RDS/PRPH2、ELOVL 和 CRB1 中可能致病的突变。
我们的研究结果强调了全外显子组测序在斯塔加特病分子诊断和研究中的巨大潜力。WES 在本研究中充分检测了 ABCA4 的所有编码序列和典型剪接位点。此外，WES 能够识别其他基因中的疾病相关等位基因。这项工作强调了为 WES 测试收集父母遗传物质的重要性，因为人类基因组变异的现有知识限制了确定所鉴定的变异与疾病之间的因果关系。虽然需要更大的样本量来确定这种测试的精度和准确性，但本研究支持将 WES 用于遗传性早发性黄斑变性疾病，作为标准突变筛查技术的替代方法。
