一先天性眼外肌纤维化综合征家系的分子遗传学及临床研究

发布时间：2018-07-03 17:08

本文选题：先天性眼外肌纤维化 + 连锁分析　；参考：《天津医科大学》2012年博士论文

【摘要】：目的 1.收集一个常染色体显性遗传先天性眼外肌纤维化综合征(Congenital fibrosis of the extraocular muscles, CFEOM)家系,分析中国人CFEOM的临床表型和遗传特点。并对家系(TT)进行基因连锁分析定位及候选基因突变检测,研究致病基因与临床表型的关系及是否有新的或已知的突变。 2.分析CFEOM家系TT患者临床特征。 3.应用MRI技术,对CFEOM家系TT部分患者进行眼球动眼神经、外展神经相关组织结构的影像学特征研究,探索发病机制,为相关的基础和临床研究提供影像学证据。方法 1.对患者及家系成员进行详细的临床检查及遗传学调查,绘制遗传图,确定遗传方式。选取分布在第12及16号染色体CFEOM1及CFEOM3区域的微卫星多态标记：D12S345、D12S59、D12S331、D12S1048用于CFEOM1型的连锁分析,D16S3063、D16S689、D16S3026、D16S3121用于CFEOM3型的连锁分析。利用聚合酶链反应(PCR)及进行单体型分析；用Linkage软件的MLINK程序对基因分型结果进行两点参数连锁分析；用直接测序的方法对家系成员的KIF21A基因的已知突变热点---第8、20、及21外显子进行突变检测,确定突变位点,并比较基因型与表型之间的相关性。 2.CFEOM家系TT患者8人,眼科检查及眼位及眼肌检查：包括眼位、眼球运动、睑裂大小、提上睑肌肌力、被动牵拉试验及Bell氏征等。 3.采用3.0T核磁对TT家系部分患者脑干行全脑、脑干的MRI薄层扫描。检测动眼神经、外展神经支。结果 1.单体型及连锁分析发现： 1)TT家系在D12S345和D12S59获得最大LOD值2.71(重组率θ=0,外显率=100%),可以肯定此家系在D12S345及D12S59紧密连锁。 2)在16号染色体上的4个标记,LOD值均小于1,不存在连锁。 2.在家系中测出KIF21A基因第21外显子的1个杂合突变：所有患者中均发现有2860CT(R954W)的错义突变,即在2860碱基的位置C变成T,这个突变对应于蛋白质的茎部区域,导致第954氨基酸位置的第1个核苷酸的改变,使一个高度保守的精氨酸被谷氨酞胺替换。 3.CFEOM家系TT属常染色体显性遗传,临床特征符合CFEOM1型,但有部分患者表现出遗传异质性,存在与CFEOM3交叉的临床特征,表现为单眼上睑下垂(Ⅱ：9)或原在位眼位正位(Ⅱ：7、Ⅲ：3)。 4.MRI薄层扫描显示TT家系中Ⅱ：5、Ⅱ：9及Ⅲ：5的眼动神经核团均显示发育不良,Ⅱ：5及Ⅲ：5患者表现动眼神经变细,右侧外展神经缺如。结论 1.T T家系的遗传方式为常染色体显性遗传,确定为CFEOM1型。 2.连锁分析将致病基因定位于12号染色体CFEOM1位点,在微卫星多态性标记D12s345和D12s59取得最大LOD值2.71。 3.测序发现TT家系突变位点位于KIF21A基因第21外显子2860CT(R954W),100名正常人无此突变。因此,KIF21A基因为该CFEOM1家系患者的致病基因。 4.家系TT证明了CFEOM1型可以有更多的表现型,这个家系被记录到和CFEOM3交叉的表现型,即临床表型的异质性。 5.脑干MRI薄层扫描结果进一步证实了该家系的病变与颅内脑干神经核团与眼动神经发育异常有关。MRI检查有助于CFEOM的临床诊断和治疗及更好的理解CFEOM的病因。
[Abstract]:objective
1. a family of Congenital fibrosis of the extraocular muscles, CFEOM was collected to analyze the clinical phenotype and genetic characteristics of Chinese CFEOM, and the gene linkage analysis and candidate gene mutation detection of the family (TT) were carried out to study the pathogenicity gene and clinical phenotype. The relationship and whether there is a new or known mutation.
2. the clinical features of TT patients in CFEOM family were analyzed.
3. the MRI technique was used to study the imaging features of oculomotor nerve and abductor nerve related tissue structure in the CFEOM family TT, and to explore the pathogenesis and provide imaging evidence for the related basic and clinical research.
Method
1. a detailed clinical examination and genetic investigation of patients and family members were conducted, genetic maps were drawn and genetic patterns were determined. Microsatellite markers distributed on the CFEOM1 and CFEOM3 regions of chromosome twelfth and 16 were selected: D12S345, D12S59, D12S331, D12S1048 for CFEOM1 type linkage analysis, D16S3063, D16S689, D16S3026, D16S3121 for CFEOM The linkage analysis of type 3. Using the polymerase chain reaction (PCR) and haplotype analysis, a two parameter linkage analysis was carried out with the MLINK program of the Linkage software, and the mutation detection of the known mutation hot spots of the family members of the family members of the family members of the family KIF21A gene, 8,20, and the 21 exon were detected by direct sequencing, and the mutation sites were determined. The correlation between genotypes and phenotypes was compared.
2.CFEOM family with 8 TT patients, ophthalmology and eye position and eye muscle examination: eye position, eye movement, the size of palpebral fissure, levator muscle strength, passive traction test and Bell's sign.
3. 3.0T nuclear magnetic resonance imaging was used to detect brainstem and abducens nerve in whole brain of brainstem of TT family and MRI thin layer scan of brainstem.
Result
1. haplotype and linkage analysis found that:
1) the TT family obtained the largest LOD value of 2.71 (recombination rate, theta =0, and penetrance =100%) in D12S345 and D12S59, and it is certain that this family is closely linked to D12S345 and D12S59.
2) 4 markers on chromosome 16 with LOD values less than 1, and there is no linkage.
2. the 1 heterozygous mutations of the KIF21A gene twenty-first exon were detected in the family. All the patients found the missense mutation of 2860CT (R954W), that is, the C changed into T at the location of the 2860 base, which corresponds to the stem region of the protein, resulting in the change of first nucleosides in the 954th amino acid position, making a highly conserved arginine by the valley. The replacement of thalidomide.
3.CFEOM family TT is an autosomal dominant inheritance. The clinical features conform to the CFEOM1 type, but some of the patients show genetic heterogeneity, and there are the clinical characteristics of the cross with CFEOM3, showing the monocular blepharoptosis (II: 9) or the original position position (II: 7, III: 3).
4.MRI TLC scan showed that in the TT family, 5, II: 9 and III: 5 of the eye movement nerve nuclei showed dysplasia, II: 5 and III: 5 patients showed a thinning oculomotor nerve and a right abduction of the abduction nerve.
conclusion
The inheritance pattern of 1.T T family is autosomal dominant and is CFEOM1 type.
2. linkage analysis loci the pathogenic gene on chromosome 12 CFEOM1, and obtains the maximum LOD value 2.71. in microsatellite polymorphism markers D12s345 and D12s59.
3. sequencing found that the TT family was located in the KIF21A gene twenty-first exon 2860CT (R954W), and 100 normal people did not have this mutation. Therefore, the KIF21A gene was the pathogenetic gene of the CFEOM1 family.
The 4. family TT proved that CFEOM1 could have more phenotype. This family was recorded to be CFEOM3 phenotype, that is, the heterogeneity of clinical phenotype.
The results of 5. brain stem MRI TLC scan further confirmed that the.MRI examination of the disease of the family and the encephalic brainstem nucleus and the dysplasia of the eye is helpful for the clinical diagnosis and treatment of CFEOM and the better understanding of the cause of CFEOM.
【学位授予单位】：天津医科大学
【学位级别】：博士
【学位授予年份】：2012
【分类号】：R777.41

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