最新的一項(xiàng)研究確定了一個(gè)與先天性黑朦(LCA)，一種嬰兒和低齡兒童最常見(jiàn)先天性失明的原因，相關(guān)的基因。
 
“這項(xiàng)新發(fā)現(xiàn)有助于快速對(duì)此疾病進(jìn)行治療。” McGill眼科基因中心主任，此項(xiàng)研究的負(fù)責(zé)人Robert Koenekoop博士說(shuō)，“我們研究的主要目標(biāo)是確定所有與兒童先天性失明相關(guān)的基因并且在隨后的研究中建立起相應(yīng)的基因治療方法以挽回喪失的視力。”

研究人員在此項(xiàng)研究中使用一種新的技術(shù)稱(chēng)為單核苷酸多態(tài)性（SNP）以確定基因組中的純合子區(qū)域，最終發(fā)現(xiàn)了這個(gè)稱(chēng)為L(zhǎng)CA5的新基因。對(duì)過(guò)去來(lái)說(shuō)，需要進(jìn)行大量家系篩選才能找到相應(yīng)的基因，但此項(xiàng)研究中，僅使用一例來(lái)自加拿大魁北克和一例來(lái)自美國(guó)的樣本就完成了此項(xiàng)研究。

SNP微序列技術(shù)可加快基因定位的速度并且使人們?cè)趲讉€(gè)月內(nèi)就能分離相應(yīng)的基因，而不是以前的幾年。“此技術(shù)在未來(lái)可能會(huì)成為確定其他視網(wǎng)膜以及導(dǎo)致失明疾病相關(guān)基因的方法。” Koenekoop博士說(shuō)道。

同一個(gè)研究小組在去年確定了CEP290基因，是導(dǎo)致LCA最普遍的基因。通過(guò)使用CEP290的蛋白結(jié)構(gòu)，研究學(xué)者發(fā)現(xiàn)了LCA5，兩者在視網(wǎng)膜中具有相似的結(jié)構(gòu)和功能。CEP290和LCA5基因編碼的蛋白在光感受器功能、視覺(jué)成像時(shí)轉(zhuǎn)運(yùn)視覺(jué)蛋白上起了重要的作用。當(dāng)這兩個(gè)基因發(fā)生突變（失明兒童中占了25-30%），視覺(jué)蛋白不能恰當(dāng)?shù)剞D(zhuǎn)運(yùn)到相應(yīng)的外層部分，導(dǎo)致光感受器停止工作并最終死亡。

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.