Epigenetic dysregulation of muscle differentiation in Kabuki syndrome

项目总结 歌舞伎综合征(KS)是一种罕见的疾病，由两个已知的杂合性致病突变引起 基因：KDM6A(~20%)和KMT2D(~80%)。这两个基因在许多 组织及其活动的时间跨度从发育到出生后的成年生活。在场的KS患者 有不同程度的临床异常，包括严重的肌肉低张和肌肉萎缩 力量。低眼压是神经传导功能障碍的结果，还是由于 骨骼肌细胞自主性原发缺陷目前尚不清楚。此外，骨骼肌组织 来自受KS影响的患者还没有得到彻底的研究。我们的主要假设是骨骼肌 组织主要受KMT2D突变的影响，KMT2D突变导致肌肉功能失调。我们 建议通过以下具体目标来验证我们的假设：1)确定主要与次要 利用KS的结构性和条件性小鼠模型的肌肉功能缺陷；2)决定基因 KMT2D在结构性和条件性KS中驱动肌肉低张的网络和分子靶点 小鼠模型；3)在条件性和结构性中定义肌肉卫星细胞的异质性和不成熟性 KS模型，以及在人类患者中。拟议的工作将填补我们在知识匮乏方面的主要空白 关于歌舞伎综合征低眼压的病因，将为患者的临床改善铺平道路 关心。

PROJECT SUMMARY Kabuki Syndrome (KS) is a rare disease caused by heterozygous pathogenic mutations in two known genes: KDM6A (~20% cases) and KMT2D (~80% cases). Both genes are broadly expressed in many tissues and their activity spans temporally from development to postnatal adult life. KS patients present with various degrees of clinical abnormalities, including severe muscular hypotonia and reduced muscle strength. Whether hypotonia develops as a consequence of nerve conduction malfunction or it is due to a cell-autonomous primary defect in skeletal muscle is currently unknown. Further, skeletal muscle tissue from patients affected by KS has not been thoroughly studied. Our main hypothesis is that skeletal muscle tissue is primarily affected by mutations in KMT2D, which results in dysregulated muscle function. We propose to validate our hypothesis via the following specific Aims: 1) Define primary versus secondary muscle function defects using constitutive and conditional mouse models of KS; 2) Determine the gene networks and molecular targets of KMT2D driving muscle hypotonia in constitutive and conditional KS mouse models; 3) Define muscle satellite cell heterogeneity and `immaturity' in conditional and constitutive KS models, as well as in human patients. The work proposed will fill major gaps in our lack of knowledge about etiology of hypotonia in Kabuki syndrome and will pave the way for clinical improvements of patient care.