新确定的与婴儿失明相关的基因

最新的一项研究确定了一个与先天性黑朦(LCA)，一种婴儿和低龄儿童最常见先天性失明的原因，相关的基因。
 
“这项新发现有助于快速对此疾病进行治疗。” McGill眼科基因中心主任，此项研究的负责人Robert Koenekoop博士说，“我们研究的主要目标是确定所有与儿童先天性失明相关的基因并且在随后的研究中建立起相应的基因治疗方法以挽回丧失的视力。”

研究人员在此项研究中使用一种新的技术称为单核苷酸多态性（SNP）以确定基因组中的纯合子区域，最终发现了这个称为LCA5的新基因。对过去来说，需要进行大量家系筛选才能找到相应的基因，但此项研究中，仅使用一例来自加拿大魁北克和一例来自美国的样本就完成了此项研究。

SNP微序列技术可加快基因定位的速度并且使人们在几个月内就能分离相应的基因，而不是以前的几年。“此技术在未来可能会成为确定其他视网膜以及导致失明疾病相关基因的方法。” Koenekoop博士说道。

同一个研究小组在去年确定了CEP290基因，是导致LCA最普遍的基因。通过使用CEP290的蛋白结构，研究学者发现了LCA5，两者在视网膜中具有相似的结构和功能。CEP290和LCA5基因编码的蛋白在光感受器功能、视觉成像时转运视觉蛋白上起了重要的作用。当这两个基因发生突变（失明儿童中占了25-30%），视觉蛋白不能恰当地转运到相应的外层部分，导致光感受器停止工作并最终死亡。

LCA: Gene Responsible for Blindness in Infants Identified

A study has identified a gene responsible for Leber Congenital Amaurosis (LCA), the most common cause of congenital blindness in infants and small children.
“This discovery has the potential to fast-track a cure for this disease,” says lead investigator Dr. Robert Koenekoop, director of the McGill Ocular Genetics Centre at the McGill University Health Centre (MUHC). “Our main research goal is to identify all the genes responsible for congenital blindness in children and then study them so that we can then use gene therapy to rescue their vision.” 

The researchers used a new technique called SNP (single nucleotide polymorphism) technology to identify homozygous regions in the genome, which led to the discovery of the new gene called LCA5. In the past, large families were necessary to find genes, but in this study only samples from one Quebec and one American patient were used to accomplish this. 

The SNP micro array technology accelerated the process of locating the gene and enabled the investigators to isolate it within a few months instead of several years. “This method may become a model for identifying other retinal diseases and causes of blindness in the future,” says Dr. Koenekoop.
 
The same international research team identified the CEP290 gene last year, the most common genetic cause of LCA . By using the protein structure of CEP290, the investigators were able to discover LCA5, as they have similar structures and functions in the retina. Both the CEP290 and LCA5 genes encode proteins with vital functions in the cilium of the photoreceptors, transporting visual proteins to the compartment where vision occurs. When these genes are mutated, which occurs in about 25 to 30 per cent of blind children, the visual proteins are not transported properly to the outer segments, causing the photoreceptors to stop working and die.