Early-onset macular degeneration with drusen in a cynomolgus monkey (Macaca fascicularis) pedigree:: exclusion of 13 candidate genes and loci
Early-onset macular degeneration with drusen in a cynomolgus monkey (Macaca fascicularis) pedigree:: exclusion of 13 candidate genes and loci
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DOI：
10.1167/iovs.04-1031
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发表时间：
2005-02-01
影响因子：
4.4
通讯作者：
Iwata, T
中科院分区：
文献类型：
--
作者：
Umeda, S;Ayyagari, R;Iwata, T
目的.描述在食蟹猴（Macaca fascicularis）中观察到的遗传性黄斑变性（其与人类年龄相关性黄斑变性具有相同的表型特征），并通过突变筛查和连锁分析来检测候选基因位点的参与。对家系中受影响和未受影响的猴进行眼底照相、荧光素血管造影（FA）、吲哚菁绿色血管造影（IA）、视网膜电图（ERG）和组织学研究的眼科检查。克隆人ABCA 4、VMD 2、EFEMP 1、TIMP 3和HPVL 4基因的猴直向同源物，并通过单链构象多态性（SSCP）分析或变性高效液相色谱（DHPLC）和直接测序在来自该谱系的6只患病和5只未患病猴以及6只无关的未患病猴中筛选突变.随后，分析了包括这五个基因在内的13个人类黄斑变性基因座，以测试与该疾病的联系。19个受影响的和7个未受影响的猴子的系谱进行了分析，使用人类微卫星标记连锁的13个位点。在黄斑和中央凹观察到黄白色斑点，并且在某些情况下斑点沿着沿着血管分散到周边视网膜。FA显示对应于除小凹中的点的高荧光。IA和ERG未发现异常。组织学研究表明这些斑点是玻璃疣。ABCA 4、VMD 2、EFEMP 1、TIMP 3和HPVVL 4基因的突变分析鉴定了一些序列变体，但它们都不与疾病分离。与这五个基因和另外八个人类黄斑变性基因座连锁的标记物的连锁分析未能建立连锁。单倍型分析排除了13个候选基因座与猴黄斑变性相关基因的关系。在猴和人的五个黄斑变性基因的直系同源物之间鉴定出显著的同源性。13个与人类黄斑变性相关的基因座或携带黄斑变性基因的基因座被排除为猴早发性黄斑变性的病因。很可能这些基因座中没有一个，而是一个新的基因，参与引起该猴谱系中观察到的表型。
PURPOSE. To describe hereditary macular degeneration observed in the cynomolgus monkey ( Macaca fascicularis), which shares phenotypic features with age- related macular degeneration in humans, and to test the involvement of candidate gene loci by mutation screening and linkage analysis.METHODS. Ophthalmic examinations with fundus photography, fluorescein angiography ( FA), indocyanine green angiography ( IA), electroretinography ( ERG), and histologic studies were performed on both affected and unaffected monkeys in the pedigree. The monkey orthologues of the human ABCA4, VMD2, EFEMP1, TIMP3, and ELOVL4 genes were cloned and screened for mutations by single- strand conformation polymorphism ( SSCP) analysis or denaturing high- performance liquid chromatography ( DHPLC) and direct sequencing in six affected and five unaffected monkeys from the pedigree and in six unrelated, unaffected monkeys. Subsequently, 13 human macular degeneration loci including these five genes were analyzed to test for linkage with the disease. Nineteen affected and seven unaffected monkeys in the pedigree were analyzed by using human microsatellite markers linked to the 13 loci.RESULTS. Yellowish white spots were observed in the macula and fovea centralis, and in some cases the spots scattered to the peripheral retina along the blood vessels. FA showed hyperfluorescence corresponding to the dots except in the foveola. No anomalies were found by IA and ERG. Histologic studies demonstrated that the spots were drusen. Mutation analysis of the ABCA4, VMD2, EFEMP1, TIMP3, and ELOVL4 genes identified a few sequence variants, but none of them segregated with the disease. Linkage analysis with markers linked to these five genes and an additional eight human macular degeneration loci failed to establish linkage. Haplotype analysis excluded the involvement of the 13 candidate loci for harboring the gene associated with macular degeneration in the monkeys.CONCLUSIONS. Significant homology was identified between monkey and human orthologues of the five macular degeneration genes. Thirteen loci associated with macular degeneration in humans or harboring macular degeneration genes were excluded as causal of early- onset macular degeneration in the monkeys. It is likely that none of these loci, but rather a novel gene, is involved in causing the observed phenotype in this monkey pedigree.