GENETIC MODELS FOR GALACTOSEMIA

半乳糖-1磷酸尿苷缺乏所致的半乳糖血症 转移酶活性(GALT)影响每50,000名新生儿中的1名。 尽管大多数州的新生儿筛查计划都很容易获得 通过限制饮食半乳糖治疗，预后为正常 身体和精神的发展没有原来那么乐观 想着。即使采用了目前最好的治疗方法，许多受影响的儿童 发育迟缓和所有受影响的女性都有初级卵巢 失败了。这项提议的第一个目标是检验这个假设 临床变异与遗传异质性有关；知识 可能导致个性化治疗，或者至少是更多的 准确的预测。因为关于发育和组织的问题 GALT缺乏症的具体影响在 人类，第二个目标将是为高尔特开发一个动物模型 缺乏，使用胚胎干细胞的基因靶向。 这项建议的具体目标是： 1.确定转移酶缺乏性半乳糖血症的基因分型及其相互关系 对临床表型的研究结果。为此，我们将： A)确定GALT改变患者的GALT基因突变的特征 按顺序分析的活动 B)通过以下方式确定GALT活性的特定突变的影响 用突变的c DNA转染半乳糖脱氨酶阴性的真核细胞 建筑。 C)在一组患者中，将基因分型结果与患者表型相关联 典型的半乳糖血症患者。 2.建立小鼠转移酶缺乏性半乳糖血症模型。至 为此，我们将： A)分离和鉴定小鼠GalT基因 B)开发一种用于电穿孔小鼠的基因打靶结构 胚胎干细胞；识别目标干细胞克隆 C)培育纯合子Galt阴性(Galt KO)小鼠，并鉴定 半乳糖毒性对胎儿发育和组织特异性的影响 这些动物的病理学。

Galactosemia due to deficiency of galactose-1 phosphate uridyl transferase activity (GALT) affects 1 in every 50,000 newborn infants. Despite newborn screening programs in most states and readily available treatment via dietary galactose restriction, the prognosis for normal physical and mental development is less optimistic than originally thought. Even with the best current therapy, many affected children are developmentally retarded and all affected females have primary ovarian failure. The first objective of this proposal is to test the hypothesis that clinical variation is related to genetic heterogeneity; knowledge of the genotype might lead to customized therapy or at least a more accurate prognosis. Because questions about developmental and tissue specific effects of GALT deficiency cannot be adequately studied in humans, the second objective will be to develop an animal model for GALT deficiency, using gene targeting in embryonic stem cells. The specific aims of this proposal are: 1. Define the genotype in transferase deficiency galactosemia and relate the finding to clinical phenotype. To do this we will: a) characterize mutations in the GALT genes of patients with altered GALT activity by sequence analysis b) determine the effect of specific mutations of GALT activity by transfecting GALT negative eucaryotic cells with mutant cDNA construction. c) correlate genotype findings with patient phenotype in a group of patients with classical galactosemia. 2. Develop a mouse model for transferase deficiency galactosemia. To do this we will: a) isolate and characterize the mouse GALT gene b) develop a gene targeting construction for electroporation into mouse embryonic stem cells; identify targeted stem cell colonies c) breed a homozygous GALT negative (GALT KO) mouse and characterize the effects of galactose toxicity on fetal development and tissue specific pathology in these animals.