MOLECULAR GENETICS OF AND GENE THERAPY FOR DEAFNESS

遗传性听力障碍患者占总数的0.05%至0.1% 美国人口。然而，遗传性听觉障碍的确切原因 分子水平上的损伤由于遗传因素而知之甚少。 耳聋的异质性。一种克服问题的策略 遗传异质性涉及对家系进行连锁分析 患有非综合征性遗传性耳聋。一个有三代人的家庭 Schiebe或耳蜗囊变性，最常见的原因是 严重的先天性听力障碍约占70% 在遗传性耳聋病例中，适合进行连锁研究的有 已被确认身份。拟议的研究项目的直接目标是 定位与Scheibe退行性变相关的基因 使用商业上可用的基因组标记的家庭。一旦链接到 人类基因组的区域是建立的，合适的候选基因 驻留在链接区域中将被标识。这些候选基因 然后将被搜索以寻找病理性突变。遗传学研究 以及随后对该基因的鉴定，当 突变，导致Scheibe变性应该大大有助于 对内脏发育和动态平衡机制的认识 耳朵。 本提案第二部分的目的是评估 腺相关病毒(AAV)在非致病性人类中的应用 在将遗传物质导入人神经上皮细胞过程中 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、呼吸道上皮细胞和多种神经细胞 细胞，内耳还没有被作为基因治疗的目标进行研究。 含有细菌β-半乳糖苷酶(β-GAL)序列的AAV， 一个标记基因，其产物很容易被检测到，将被注入 在渗透性小泵的帮助下有选择地进入耳蜗腔。这个 将在不同的时间间隔研究注入的耳蜗-转导到 评估甲型肝炎病毒感染的特异性和稳定性。从实验上看， 将基因导入内耳的能力将有助于 了解耳蜗蛋白的功能与内耳的控制 特定的基因。在治疗上，迅速交付神经营养物质 这些因素可以减少组织损伤，保护听力。 受伤。位置克隆在几个大家系中的研究 遗传性、非综合征性听力障碍是潜在的 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以及 为听力的分子遗传学分析做出了贡献。

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.