一个晶状体脱位家系的连锁分析及临床回顾性研究

发布时间：2018-05-14 22:03

本文选题：晶状体脱位 + 马凡氏综合征　；参考：《天津医科大学》2010年博士论文

【摘要】： 目的应用连锁分析、基因测序的方法,对一个常染色体显性遗传的晶状体脱位(Ectopia lentis, EL)家系进行基因筛查及定位,探讨该家系的发病原因；分析该家系的临床特点,回顾总结该家系的治疗效果及并发症,讨论晶状体脱位的治疗方法。方法 1分子遗传学研究 1.1取家系成员外周血5-8ml,采用Roche Biochemical公司的DNA分离试剂盒提取基因组DNA。 1.2基因分型和连锁分析：选取15号染色体上微卫星标记物进行基因组扫描。利用聚合酶链反应扩增微卫星标记物,通过ABI3130-avant全自动分析仪读取微卫星标记物的等位基因片段大小,应用Genescan3.7软件进行单体型结构分析,利用LINKAGE5.1软件包中MLINK程序进行两点法计算LOD值,并构建单体型。 1.3基因序列分析：对所有家系患病成员及正常同胞进行FBN-1基因全部编码序列分析,包括FBN1基因的全部65个外显子,5’及3’端与外显子拼接的内含子序列。通过ABI3130测序仪读取基因序列。利用单链构象多态性分析对突变基因进行筛查。 2.回顾性临床研究 2.1 EL家系患者的临床特点 2.2 EL家系患者病史采集。收集原始病历,分别进行视力,屈光状态,裂隙灯,前节照相,超声生物显微镜(UBM)检查,眼底等眼部检查。同时注意全身情况,尤其注意骨骼系统包括身高四肢及心血管系统如心脏超声波的检查。 2.3该家系患者晶状体脱位的治疗用晶状体囊内摘除法。结果 1分子遗传学研究经过对15号染色体上的微卫星位点进行连锁分析并计算LOD值,发现在15号染色体着丝粒附近的两个微卫星标记物D15S994和D15S978均获得正值,其中在D15S978取得最大LOD值为3.01。单体型分析发现该家系临床表型与D15S978等位基因片段存在共分离现象,支持该家系致病基因位于常染色体15q21.1-15q21.3区间。在此区间内的候选基因FBN1与晶状体脱位以及MARFAN综合征的发病相关。对FBN1基因直接测序显示家系中所有患者在FBN1基因的第29外显子存在杂和性突变,mRNA第3519位碱基出现C→G的杂合性碱基改变,导致了野生型基因编码的谷氨酰胺(Asparagine, Asn或N)被赖氨酸(Lysine, Lys或K)替代,使第1173编码子发生了N1173K的突变,并且该突变与疾病表型共分离。通过SSCP筛查100名正常对照未发现类似改变,说明c.C3519T(p.Asn1173Lys)为致病性基因突变,而非多态性碱基序列改变。说明FBN1基因c.C3519T(p.Asn1173Lys)突变是导致该家系的致病性基因突变。 2临床研究 2.1临床表现该EL家系三代同胞13人,共有8名患者,男5例女3例。具有完全外显的常染色体显性遗传特性。患者的临床特征都表现为晶状体脱位,均向颞侧脱位,脱离范围大于1／2。该家系患者多数在30岁以后视力逐渐下降,之前均为1.0视力(主诉)。身高无明显马凡氏特征。复习以前的病历诊断均为原发性晶状体脱位。但是只有1名患者(第三代,待手术。照片1左1),身高及相貌类似马凡氏特征,但超声心动图检查无明显阳性体征,建议随访观察。其他患者也无心血管系统的阳性发现。因此不能诊断为马凡氏综合征。因此我们将该家系诊断为原发性晶状体脱位。 2.2治疗效果及并发症：家系8名患者6例已行晶状体囊内摘除术。6例(8眼)患者手术后矫正视力均较术前明显提高；1例1眼术前矫正视力1.0,因为对侧眼发生晶状体全脱位,导致失明,因此为防止晶状体全脱位要求手术,术后矫正视力0.6。有3例3眼发生晶状体全脱位于前房,合并继发性青光眼,急诊手术取出晶状体,术后角膜失代偿,2例导致失明,1例矫正视力0.3。1例1眼术后10年发生黄斑出血,视网膜脱离,手动视力。因此目前该家系术后12眼失明3眼。2例4眼仍然待手术。结论 1确定了一个常染色体显性遗传的晶状体脱位家系,家系同胞13人,8名患者。经序列分析发现晶状体脱位家系患者均存在FBN-1基因第29外显子的N1173K突变。SSCP分析证实了这一突变于与疾病表型共分离。因此,FBN1基因c.C3519T(p.Asn1173Lys)突变可能是导致该家系的致病性基因突变。 2家系患者间表现型存在异质性。第三代1名患者身高与马凡氏综合征类似,而第一代与第二代身高无明显异常。 3晶状体脱位的手术时机应恰当选择,发生晶状体全脱位后预后较差。
[Abstract]:objective
Using the method of linkage analysis and gene sequencing, the genetic screening and localization of an autosomal dominant Ectopia lentis (EL) family were carried out to explore the causes of the family, the clinical characteristics of the family, the therapeutic effects and complications of the family, and the treatment of the dislocation of the lens were reviewed and summarized.
Method
1 molecular genetics research
1.1 the peripheral blood 5-8ml of family members was extracted and genomic DNA. was extracted by Roche Biochemical DNA separation kit.
1.2 genotyping and linkage analysis: the microsatellite markers on chromosome 15 were selected for genome scans. The microsatellite markers were amplified by polymerase chain reaction, and the size of the allele fragments of microsatellite markers was read by ABI3130-avant automatic analyzer, and Genescan3.7 software was used to analyze the haplotype structure and use LINKAGE5 The MLINK program in the.1 software package calculates the LOD value by two point method and constructs the haplotype.
1.3 gene sequence analysis: all family members and normal compatriots in all the FBN-1 gene sequence analysis, including all 65 exons of the FBN1 gene, 5 'and 3' end and exons intron sequence. The gene sequence was read by ABI3130 sequencer. Single strand conformation polymorphism analysis was used to screen the mutant gene. Check.
2. retrospective clinical study
Clinical characteristics of 2.1 EL families
2.2 EL family history collection. Collect the original medical records for visual acuity, refractive state, slit lamp, anterior segment photography, ultrasound biomicroscope (UBM) examination, eye fundus and other eye examination. Meanwhile, pay attention to the whole body, especially the skeletal system including the height and limbs and the heart blood tube system such as echocardiography.
2.3 the removal of lens dislocation in the family is treated by intracapsular cataract extraction.
Result
1 molecular genetics research
After linkage analysis of the microsatellite sites on chromosome 15 and calculating the LOD value, it was found that two microsatellite markers near the 15 chromosome centromere of the 15 chromosome were positive. The maximum LOD value of D15S978 was 3.01. haplotype analysis and found that the family bed phenotype and D15S978 allele fragments existed in common. The segregation phenomenon supports the disease gene of the family in the autosomal 15q21.1-15q21.3 interval. The candidate gene FBN1 in this interval is associated with the dislocation of the lens and the incidence of MARFAN syndrome.
Direct sequencing of the FBN1 gene showed that all the patients in the family had a heterozygous mutation in the twenty-ninth exon of the FBN1 gene, and the heterozygosity of the mRNA 3519th bases appeared C to G, which led to the substitution of the glutamine (Asparagine, Asn or N) encoded by the wild type gene by lysine (Lysine, Lys or K), and the 1173rd codons occurred in N1173K. 100 normal controls were screened by SSCP without similar changes, indicating that c.C3519T (p.Asn1173Lys) was a pathogenicity gene mutation, not a polymorphic base sequence change. The FBN1 gene c.C3519T (p.Asn1173Lys) mutation was a pathogenic gene mutation leading to the family.
2 clinical study
2.1 the clinical manifestations of the EL family were 13 people of three generation compatriots. There were 8 patients and 5 male and 3 women. The clinical features of the patients were completely autosomal dominant. The clinical features of the patients showed dislocation of the lens, the temporal dislocation of the patients were more than 1 / 2., and the majority of the families were gradually decreased after the age of 30, and all were 1 visual acuity. There was no obvious Marfan characteristic of height. Review of previous medical records were all primary lens dislocation. But only 1 patients (third generation, surgery, 1 left 1), height and appearance resembling the Marfan features, but no obvious positive signs were found in echocardiography. Therefore, we can not diagnose Marfan's syndrome. Therefore, we diagnosed this family as primary lens dislocation.
2.2 treatment effect and complications: 6 cases of 8 patients in the family had undergone intraocular lens extirpation in 6 cases (8 eyes). The corrected visual acuity after operation was significantly higher than that before operation. 1 cases 1 eyes corrected visual acuity before operation 1, because of the total dislocation of the lens in the lateral eye, resulting in blindness, so the operation was required to prevent the total dislocation of the lens, and the corrected visual acuity was 0.6. after operation. In 3 cases, 3 eyes had complete lens detachment in the anterior chamber, combined with secondary glaucoma, emergency surgery to remove the lens, postoperative corneal decompensation, 2 cases of blindness, 1 cases of corrected visual acuity in 0.3.1 1 eyes and 10 years after the operation of macular hemorrhage, retinal detachment, and manual vision. So at present, 12 eyes, 3 eyes, and 4 eyes, 4 eyes and 4 eyes of 3 eyes still remain to be operated.
conclusion
1 a family of autosomal dominant hereditary lens dislocation, 13 people in family and 8 patients, the N1173K mutation.SSCP analysis of the FBN-1 gene twenty-ninth exon confirmed by sequence analysis that the mutation was common to the disease phenotype. Therefore, the FBN1 gene c.C3519T (p.Asn1173Lys) mutation can be found. It can be a pathogenic gene mutation that leads to the family.
There was heterogeneity between the 2 family patients. The height of third generation 1 patients was similar to Marfan syndrome, but there was no significant difference between the first and second generations.
3 the operation time of lens dislocation should be properly chosen. The prognosis of lens dislocation is poor.

【学位授予单位】：天津医科大学
【学位级别】：博士
【学位授予年份】：2010
【分类号】：R776

【相似文献】