常隐遗传迟发性脊柱骨骺发育不良家系新致病基因ESRRB鉴定及功能研究

Spondylo epiphyseal dysplasia (SED) were genetic heterogeneous bone diseases characterized by onset in childhood, growth retardation, disproportionately short trunk and thoracolumbar vertebral flat. These diseases were in autosomal dominant, autosomal recessive, X-chromosomal inheritance and sporadic cases. Recently, significant progress has been made in virulence gene research of this disease. The genes mutated have been identified as SEDL, COL2A1 WISP3, CHST3, ACAN, EIF2AK3, MATN3 and PAPSS2. However, the virulence genes of many hereditary and sporadic cases have not been found and lead to the diagnosis of the disease and intervention lagging behind. In our previous study, we found the new virulence ESRRB gene mutation (R6G) using the whole-exome sequencing method in the proband of autosomal recessive SEDT who had family histories of consanguineous marriage.Therefore, we intend to use direct sequencing method to identified ESRRB gene mutation in other two SEDT family of consanguineous marriage and 22 patients without family history. And we will do functional studies after that. The ESRRB gene mutant will be transferred to the cultured C20/A4 and C3H10T1/2 cell lines. We observed biological behavior, CDMP-1 and other markers of cartilage expression. The prsent study will provide experimental evidence for identification new virulence gene ESRRB caused SEDT and clarification the molecular mechanism of the gene.

脊柱骨骺发育不全(SED)是以儿童期起病、生长迟缓、短躯干型个矮及脊柱椎体扁平为特征，严重影响青少年骨骼发育的遗传性骨病，呈常显、常隐、X连锁遗传或散发病例。近年SED致病基因研究获得重大突破，鉴定了SEDL、COL2A1、WISP3、CHST3、ACAN、EIF2AK3、MATN3和PAPSS2等基因。但仍有一些遗传或散发病例致病基因不明确，以致未能明确诊断和开展产前干预。我们前期使用外显子测序法在一个近亲常隐遗传迟发性SED(SEDT)家系发现ESRRB基因R6G位点突变，本项目拟筛查另二家近亲SEDT家系和22例散发患者的ESRRB基因；同时开展功能研究：构建ESRRB基因突变体，研究转染突变体的C20/A4和C3H10T1/2细胞株软骨细胞生物学行为和aggrecan、CDMP-1等软骨标志的表达。本项目为确定ESRRB是常隐遗传迟发性SED的新致病基因及其发病机制提供重要依据。

脊柱骨骺发育不全（spondylo epiphyseal dysplasia，SED），属于典型的单基因遗传病，是以生长发育迟缓,以不成比例的短躯干型个矮及胸腰椎椎体扁平为特征的一类遗传性骨病。常由于基因突变引起骨软骨发育障碍,病变主要累及腰椎和近端承重大关节。目前已阐明SED致病基因包括：SEDL、COL2A1、WISP3、CHST3、ACAN(AGCl)、EIF2AK3、 MATN3和PAPSS2等。迟发性常染色体隐性SED患者致病基因尚不清楚，因此本项目重点是我们利用常染色体隐性SEDT家系，明确致病基因，同时阐明其发病的分子机制。.我们在临床上诊治了四个常染色体隐性SEDT的家系（家系1-4），已通过鉴别诊断以及已知致病基因突变检测，已经排除骨质疏松症、幼年型类风湿关节炎、常染色体显性及X 染色体连锁隐性SEDT等疾病。另外我们又收集到一家脊柱骨骺发育不全的大家系（家系5），同时收集了该家系中13个血液样本。.根据先证者的临床表现、影像学检查及家系遗传方式，初步诊断为迟发性脊柱骨骺发育不良伴进行性骨关节病(SEDT-PA)。该病是常染色体隐性遗传疾病，其致病基因WISP3定位于6q22-23,编码蛋白为Wntl-诱导信号通路蛋白-3。4个家系先证者中均发现WISP3基因纯合突变或复合杂合突变，突变位点均具致病性。其中家系1中的突变位点p.Cys209MetfsX21、家系2突变位点p.Tyr116X、家系3突变位点p.Cys114Trp和家系4的突变位点p.Cys223Gly均为首次报道的新发现位点。目前已整理成文，在投稿中。在我们寻找到的一个脊柱骨骺干骺端发育不全大家系5，已经排除已知致病基因突变，后续进一步寻找其他致病基因，有望获得突破。.迟发性脊柱骨骺发育不良伴进行性骨关节病是一种少见的常染色体隐性遗传性疾病，临床特点及典型的影像学表现有助于诊断。并首次发现了WISP3基因4个新突变位点，开展WISP3基因检测以确诊。对一个脊柱骨骺干骺端发育不全大家系已经获得连锁区域，排除已知基因突变，明确为新致病基因突变导致，后续进行鉴定。