Genetic screening and therapies for nemaline myopathies

描述（由申请人提供）：本项目的长期目标是完成我们对线虫性肌病（NM）遗传基础的理解，目的是开发适用于新生儿筛查计划的快速遗传诊断测试，并为通过此类筛查确定的NM常见原因之一开发有效和创新的疗法。线状体肌病是一组遗传异质的密切相关的先天性肌病，定义的基础上先天性表现为中度至重度骨骼肌无力和肌肉活检显示受影响儿童的肌纤维中的线状体杆。这些疾病的统一分子特征是，七个已知基因中有六个编码肌动蛋白细丝的成分，使其成为肌节疾病。尽管利用作图和候选基因分析进行了广泛的遗传调查，但许多病例的遗传基础仍然未知。然而，下一代DNA测序的出现以及全外显子组和基因组测序的可用性使得以快速和具有成本效益的方式进行全面的遗传研究成为可能。将利用全外显子组测序完成NM患者的大型和良好表征的队列的遗传分析，并且基于这些结果，将设计特异性DNA捕获芯片以促进NM和相关先天性肌病的所有基因的快速分析，用于筛选低渗和虚弱的新生儿。缺乏有效的NM疗法，并且其开发的主要障碍是缺乏适合于筛选潜在治疗化合物的模型系统。为了解决这个问题，将开发和表征骨骼肌动蛋白（ACTA 1基因）相关NM（NEM3）的斑马鱼模型，并用于高通量药物筛选，以鉴定具有治疗原发性骨骼肌病变和肌营养不良患者NM和相关疾病潜力的先导化合物。这种有效和敏感的新生儿DNA为基础的筛查方案的发展将允许快速和准确的诊断，消除了需要更多的侵入性和风险的程序，如肌肉活检，并将允许早期预后的确定，携带者测试在风险亲属，以防止未来受影响的儿童出生，并将允许optial早期医疗管理。新的治疗化合物和方法的鉴定将为新疗法的临床前测试奠定基础，这些新疗法有朝一日可能用于治疗患有这些毁灭性神经肌肉疾病的儿童。这些进展也将增加我们对基本肌肉生物学的了解，并对我们理解其他神经肌肉疾病产生影响。

DESCRIPTION (provided by applicant): The long-term goals of this project are to complete our understanding of the genetic basis for the nemaline myopathies (NMs) with the aim of developing rapid genetic diagnostic tests suitable for newborn screening programs, and to develop effective and innovative therapies for one of the common causes of NM that would be identified through such screening. The nemaline myopathies are a genetically heterogeneous group of closely related congenital myopathies, defined on the basis of congenital presentation of moderate to profound skeletal muscle weakness and muscle biopsy revealing nemaline rods in myofibers of affected children. The unifying molecular feature of these conditions is that fact that six of the seven known genes encode components of the actin thin filament, making this a disease of the sarcomere. Despite extensive genetic investigations utilizing mapping and candidate gene analysis, the genetic basis for many cases remains unknown. However, the advent of next generation DNA sequencing, and availability of whole exome and genome sequencing makes comprehensive genetic studies feasible in a rapid and cost-effective manner. Whole exome sequencing will be utilized to complete the genetic analysis of a large and well- characterized cohort of NM patients, and on the basis of these results, a specific DNA capture chip will be designed to facilitate rapid analysis of all the genes for NM and related congenital myopathies for use in screening hypotonic and weak newborns. Effective therapies for NM are lacking, and a major hurdle to their development is absence of model systems suitable for screening potential therapeutic compounds. To address this problem, zebrafish models of skeletal actin (ACTA1 gene) related NM (NEM3) will be developed and characterized, and utilized in high throughput drug screens to identify lead compounds with therapeutic potential for NM and related disorders in patients with primary skeletal myopathies and muscular dystrophies. Development of this efficient and sensitive newborn DNA-based screening protocol will allow for rapid and accurate diagnosis, eliminating the need for more invasive and risky procedures such as muscle biopsy, and will allow for early prognostic determinations, carrier testing in at risk relatives to prevent births of future affected children, and will allow for optial early medical management. Identification of new therapeutic compounds and approaches will set the stage for preclinical testing of new therapies that may one day be used to treat children with these devastating neuromuscular diseases. These advances will also increase our knowledge of basic muscle biology with implications for our understanding of other neuromuscular diseases.