人SLC25A13基因突变影响肝细胞线粒体内膜AGC2功能而形成严重危害我国婴儿健康的遗传病NICCD。我们近期研究结果提示：人PBLs除了表达AGC2，其特定亚群中SLC25A13可能还编码一种具备AGC亚细胞定位能力和载体功能、可用于NICCD诊断的新亚型AGC3，但这一假说需要实验验证。本项目用淋巴细胞分选、cDNA克隆和蛋白印迹等技术研究SLC25A13编码的AGC亚型在人PBLs不同亚群的分布特点；以cDNA重组、免疫印迹和共聚焦显微镜等方法比较AGC亚型结构并探讨其功能和亚细胞定位；在以上研究基础上，借助家系SNP分析等方法识别NICCD患儿SLC25A13隐匿突变并通过重组变异体功能分析等技术研究新突变致病性。本项目将揭示人PBLs特定亚群AGC亚型的表达特征，为SLC25A13产物分析提供新标本来源和分子标志，为NICCD患儿确诊提供新实验依据，具有重要理论价值和科学意义。

Mutations of human SLC25A13 gene impair the function of Aspartate-Glutamate Carrier isoform 2 (AGC2), leading to the formation of Neonatal Intrahepatic Cholestasis caused by Citrin Deficiency (NICCD), a genetic disease that remains a serious challenge against the infant health in China. Our recent research findings suggest that, besides AGC2 expressed in human peripheral blood lymphocytes (PBLs), SLC25A13 gene in specific lymphocyte subpopulations might encode AGC3, a novel isoform that harbors the AGC subcellular localization ability and carrier function, and can be used as a novel molecular marker for NICCD diagnosis. This hypothesis, however, needs to be verified by detailed experimental tests. This project was designed to explore the distribution feature of SLC25A13-encoded AGC isoforms, including AGC2 and AGC3, in diverse subpopulations of human PBLs by using such techniques as lymphocyte sorting, cDNA cloning and Western blot; and to compare the structures of the AGC isoforms and to investigate their function and subcellular localization by means of cDNA recombination, immunoblot and confocal microscopy as well; moreover, according to the findings of the above studies, to further identify the insidious SLC25A13 mutations with familial SNP analysis and other methods in NICCD patients, and to explore the pathogenecity of novel SLC25A13 mutations by utilizing the tools such as functional analysis of the corresponding recombinant variants. The project will reveal the expression characteristics of the AGC isoforms in specific subpopulations of human PBLs, provide new sample source and molecular markers for the analysis of SLC25A13 products, and supply new laboratory evidences for the definite diagnosis of NICCD infants, therefore having great theoretical value and scientific significance.