MOLECULAR GENETICS OF AND GENE THERAPY FOR DEAFNESS

遗传性听力障碍影响总数的0.05%至0.1% 美国人口。 然而，遗传性听觉障碍的确切原因 由于遗传因素，分子水平上的损伤知之甚少。 耳聋的异质性 一种克服问题的策略， 遗传异质性包括对家系进行连锁分析 非综合征遗传性耳聋 一个三代同堂的家庭 Schiebe或耳蜗囊状变性，最常见的原因， 严重的先天性听力障碍约占70% 遗传性耳聋的病例，这是适合连锁研究， 被识别。 拟议研究项目的近期目标是 为了定位负责Scheibe变性的基因， 使用商业上可获得的基因组标记的家族。 一旦链接到一个 在建立人类基因组的区域时， 将识别位于链接区域中的。 这些候选基因 将被用来寻找病理性突变。 遗传研究 以及随后鉴定出的基因， 突变，导致Scheibe变性， 了解内分泌系统的发育和稳态机制， 耳朵 本建议第二部分的目的是评估 腺相关病毒（AAV，一种非致病性人类病毒）的应用 细小病毒）将遗传物质引入神经上皮细胞， 内耳 虽然基因转移已经成功地在 大量的有丝分裂后细胞如肌管，肝细胞， 内皮细胞、气道上皮细胞和多种神经元细胞 细胞，尚未将内耳作为基因治疗的靶点进行研究。 含有细菌β-半乳糖苷酶（β-gal）序列的AAV， 一种其产物易于检测的标记基因将被注入 在渗透微型泵的帮助下选择性地进入耳蜗。 的 将以不同的间隔-转导研究灌注耳蜗， 评估AAV感染的特异性和稳定性。 在实验上， 将基因导入内耳的能力将有助于 了解耳蜗蛋白的功能和内耳的控制 特定基因治疗上，及时给予神经营养素 这些因素可以减少组织损伤并保护听力 损伤 几个大家系的定位克隆研究 遗传性、非综合征性听力障碍代表着潜在 基因治疗的候选基因。 这些研究将有助于设计 缓解听觉功能障碍的治疗策略， 有助于听力的分子遗传学分析。

Hereditary hearing impairment affects between 0.05 to 0.1% of the total US population. However, the precise cause of inherited auditory impairment at the molecular level is poorly understood due to the genetic heterogeneity of deafness. A strategy that overcomes the problem with genetic heterogeneity involves carrying out linkage analysis on families with nonsyndromic hereditary deafness. A three generation family with Schiebe or cochleosaccular degeneration, the most common cause of profound, congenital hearing impairment accounting for approximately 70% of cases of hereditary deafness, that is suitable for linkage studies has been identified. The immediate goal of the proposed research project is to map the location of gene responsible for Scheibe degeneration in this family using commercially available genomic markers. Once linkage to a region of the human genome is established, suitable candidate genes that reside in the linked region will be identified. These candidate genes will then be searched for the pathological mutation. The genetic study of this family and the subsequent identification of the gene which, when mutated, results in Scheibe degeneration should greatly aid in the understanding of the development and homeostatic mechanisms of the inner ear. The purpose of the second component of this proposal is to assess the utility of adeno-associated virus (AAV, a non-pathogenic human parvovirus) in introducing genetic material into the neuroepithelia of the inner ear. While gene transfer has been successfully performed in a large variety of post-mitotic cells such as myotubes, hepatocytes, endothelial cells, airway epithelial cells, and a variety of neuronal cells, the inner ear has not been studied as a target for gene therapy. The AAV containing the bacterial beta-galactosidase (beta-gal) sequence, a marker gene whose product is readily detectable, will be infused selectively into the cochlea with the aid of an osmotic minipump. The infused cochleas will be studied at various interval-transduction to assess the specificity and stability of AAV infection. Experimentally, the ability to introduce genes into the inner ear will aid in the understanding the function of cochlear proteins and control of inner ear specific genes. Therapeutically, the prompt delivery of neurotrophic factors could reduce the tissue damage and preserve hearing following injury. Positional cloning studies in several large families with hereditary, non-syndromic hearing impairment represent potential candidate genes for gene therapy. These studies will aid in designing therapeutic strategies to alleviate auditory dysfunction as well as contributing towards molecular genetic analysis of hearing.