Whole-exome sequencing revealed HKDC1 as a candidate gene associated with autosomal-recessive retinitis pigmentosa
Whole-exome sequencing revealed HKDC1 as a candidate gene associated with autosomal-recessive retinitis pigmentosa
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全外显子组测序显示 HKDC1 是与常染色体隐性视网膜色素变性相关的候选基因
DOI：
10.1093/hmg/ddy281
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发表时间：
2018
影响因子：
3.5
通讯作者：
Zhu Xianjun
中科院分区：
文献类型：
--
作者：
Zhang Lin;Sun Zixi;Zhao Peiquan;Huang Lulin;Xu Mingchu;Yang Yeming;Chen Xue;Lu Fang;Zhang Xiang;Wang Hui;Zhang Shanshan;Liu Wenjing;Jiang Zhilin;Ma Shi;Chen Rui;Zhao Chen;Yang Zhenglin;Sui Ruifang;Zhu Xianjun
色素性视网膜炎（RP）是一种可导致失明的遗传性视网膜退行性疾病。尽管已鉴定出 70 个与 RP 相关的基因，但约 40% RP 患者的遗传原因仍有待阐明。对 68 个未解决病例的 RP 队列的先证者应用全外显子组测序，以确定候选基因突变。在两个表现迟发性视网膜变性的无关家族的 HKDC1 中发现纯合错义变异（c.173C > T，p.T58 M）。这种变异影响高度保守的氨基酸残基，在多个数据库中非常罕见，并且在 4000 个种族匹配的对照中不存在。突变的HKDC1蛋白部分失去了己糖激酶活性。Hkdc1在小鼠视网膜中表达并定位于光感受器内节。为了阐明Hkdc1在视网膜中的体内作用，我们使用CRISPR/Cas9技术生成了Hkdc1敲除（KO）小鼠模型。鉴定出两个独立的等位基因，并与 C57BL/6 J 回交 6 代。通过使用 HKDC1 抗体进行蛋白质印迹和免疫染色，证实了 HKDC1KO 视网膜中不存在 HKDC1 表达。Hkdc1KO 小鼠表现出暗视视网膜电图反应减弱和外核层变薄，与一些人类患者表型相似。 HKdc1 的缺失导致视紫红质错误定位到视网膜某些区域的视杆内节和细胞体。综上所述，我们的数据表明 HKDC1 与常染色体隐性遗传 RP 相关。
Retinitis pigmentosa (RP) is an inheritable retina degenerative disease leading to blindness. Despite the identification of 70 genes associated with RP, the genetic cause of ∼40% of RP patients remains to be elucidated. Whole-exome sequencing was applied on the probands of a RP cohort of 68 unsolved cases to identify candidate genetic mutations. A homozygous missense variant (c.173C > T, p.T58 M) was found inHKDC1in two unrelated families presenting late-onset retinal degeneration. This variant affects highly conserved amino acid residue and is very rare in several databases and absent in 4000 ethnic-matched controls. Mutant HKDC1 protein partially lost hexokinase activity.Hkdc1is expressed in the mouse retina and localized to photoreceptor inner segments. To elucidate thein vivoroles ofHkdc1in the retina, we generatedHkdc1knockout (KO) mouse models using CRISPR/Cas9 technique. Two independent alleles were identified and backcrossed to C57BL/6 J for 6 generations. Absence of HKDC1 expression in theHkdc1KO retina was confirmed by western blot and immunostaning using HKDC1 antibody.Hkdc1KO mice exhibited reduced scotopic electroretinogram response and thinner outer nuclear layer, similar to some of the human patient phenotypes. Loss ofHkdc1led to mislocalization of rhodopsin to the inner segments and cell bodies of rods in some regions in the retina. Taken together, our data demonstrated thatHKDC1is associated with autosomal recessively inherited RP.