A MURINE MODEL OF SMITH-MAGENIS SYNDROME

Smith-Magenis综合征（SMS）是一种与人类染色体l7p11.2杂合缺失相关的多发性先天性异常智力低下综合征。这种微缺失综合征的出生发生率估计为20- 25000分之一，使其成为人类中最常见的染色体缺失之一。临床特征包括智力低下、周围神经病变、身材矮小、轻微颅面异常、手指短、小角膜、心脏和肾脏发育缺陷以及神经行为异常。复杂的表型表明几个连续基因的缺失，并假设是由单倍不足造成的。虽然在SMS共同缺失间隔中已经确定了几个基因，但它们对这种复杂表型的贡献仍然是推测性的。染色体17p11.2与小鼠11号染色体32-34 cM区域同源。一些基因已经被定位到小鼠和人类的合成区域。l7p11.2中的其他基因也可能有小鼠同源物。本研究旨在通过使用染色体工程技术构建小鼠11号染色体上与人类SMS缺失间隔相同的区域的缺失，来确定哪个基因或一组基因负责SMS。然后将对工程小鼠进行广泛的表征，以确定基因单倍不全的后果。这些分析将有助于了解SMS染色体微缺失综合征的分子基础，并将对人类发育和生物学产生重大影响。本提案的职业发展目标旨在为候选人提供必要的人类疾病基因鉴定和分析工具，以及开发人类疾病的小鼠模型的能力。贝勒医学院为开发小鼠模型提供了无与伦比的环境，非常适合为学术医学事业准备高度积极的个人。受指导科学家发展奖将进一步促进这一进程。

Smith-Magenis syndrome (SMS) is a multiple congenital anomaly mental retardation syndrome associated with a heterozygous deletion of human chromosome l7p11.2. This microdeletion syndrome has an estimated birth incidence of 1 in 20-25,000, making it one of the most frequently observed chromosomal deletions in humans. Clinical features include mental retardation, peripheral neuropathy, short stature, minor craniofacial anomalies, short fingers, microcornea, developmental defects of the heart and kidneys, and neurobehavioral abnormalities. The complex phenotype suggests deletion of several contiguous genes and is hypothesized to result from haploinsufficiency. Although several genes have been identified in the SMS common deletion interval, their contribution to this complex phenotype remains speculative. Chromosome 17p11.2 is syntenic to the 32-34 cM region of murine chromosome 11. Several genes have been mapped to both the mouse and human regions of synteny. Other genes in l7p11.2 also likely have murine homologues. This proposal seeks to characterize which gene or group of genes is responsible for SMS by using chromosome engineering to construct deletions of those regions of mouse chromosome 11 that are syntenic for the human SMS deletion interval. Extensive characterization of the engineered mice will then be performed to determine the consequences of gene haploinsufficiency. These analyses will contribute to the understanding of the molecular basis of the SMS chromosomal microdeletion syndrome and will have potent implications for human development and biology. The career development aims of this proposal have been designed to provide the candidate with the tools necessary for human disease gene identification and analysis as well as with the capability of developing murine models of human disease. Baylor College of Medicine provides an environment that is unparalleled for developing murine models and that is ideally suited to prepare highly motivated individuals for careers in academic medicine. The Mentored Scientist Development Award would further facilitate this process.