Clinical Analysis And PAX6Gene Association Study Of A Chinese Family With Autosomal Dominant Congenital Aniridia

Chapter1Classical genetic and clinical analysis of a Chinese family with autosomal dominant congenital aniridiaObjective:The purpose of this study was to analysis the inheritance pattern and clinical features of a Chinese family with congenital aniridia.Methods:A detailed pedigree survey was made on a family(ANL) with congenital aniridia that was under treatment of the Second Xiangya Hospital of Central South University, and its pedigree tree was draw. Detailed history and eyes examination of the9patients that voluntarily participate in this survey was taken. Four patients that could get a clear macular optical coherence tomography (OCT) graphs use the retinal thickness analyzed automatically by instrument according to macular9-grid partition. The macular reading in the central partition was treated as the central retinal thickness; the average value of retinal thickness at upper inner circle, inner circle of the nose sides, lower inner circle, bitamporal inner circle was treated as the retinal thickness of inner circle of parafoveal area; the average value of retinal thickness at upper outer circle, outer circle of the nose sides, lower outer circle, bitamporal outer circle was treated as the retinal thickness of outer circle of parafoveal area. At the same time, ten normal volunteers as selected as a control group.Result:The ANL family with congenital aniridia lived up to the diagnostic criteria of autosomal dominant inheritance. In ANL Pedigree, under the same family conditions, best corrected visual acuity (BCVA) of the older was worse than the young, while under the same age, the BCVA of peasant family was worse than worker's family. The retinal thickness of central district was290.38±12.49μm, the retinal thickness of the inner concave circle of parafoveal area was298.34±14.26μm, and the retinal thickness of the outer concave circle of parafoveal area was267.22±11.27μm; compared to normal volunteers, the former P<0.05, and the latter two are>0.05. About the propositus Ⅲ:9, the bottom of his right eye crystal temporal was sliced-shaped, and his left eye had been done cataract surgery and small incision foldable IOL implantation, in the surgery the anterior capsule was fragile, and there was a serious glare after the surgery. Patient Ⅲ:16concomitanted with schizophrenia. Patient Ⅳ:18concomitanted with mental disorders but did not part, and also concomitanted with congenital glaucoma. Patient Ⅳ:16has the largest amount of iris tissues in9interviewees, and the iris tissues in the left eyes is more than that of the right eyes, and there is persistent pupillary membrane in superior-nasal pupillary zone in left eye.Conclusion:(1) The inheritance pattern of ANL with congenital aniridia was autosomal dominant inheritance;(2) the BCVA of Congenital Aniridia might be related to the photic injury of lens and retina with age;(3) the main performance of the congenital Aniridia foveal hypoplasis was that the marked thickening of the macula center, and the central recess has layers of retina structure in addition to the nerve fiber layer;(4) the lens morphology of patients with congenital aniridia could have an abnormal development, and its cataract may develop rapidly after reaching a certain degree;(5) fragile anterior capsule and visual quality after the surgery need to be taken into consideration when having cataract surgery on congenital aniridia patients;(6) there is a phenotypic variation of iris morphology and mental illness in ANL Pedigree with Congenital Aniridia;(7) the persistent pupillary membrane of Congenital Aniridia patients is supported by the doctrine of too much iris atrophy in congenital aniridia pathogenesis. Chapter2Sequencing and copy number variation of PAX6gene ofa Chinese family with autosomal dominant congenital aniridiaObjective:To determine a Chinese family with autosomal dominant congenital aniridia whether had mutation or copy number variation of PAX6gene.Methods:Total genomic DNA was isolated from peripheral blood of the propositus Ⅲ:9of a Chinese family with autosomal dominant congenital aniridia. Two promoter regions,5'-untranslated region (5'-UTR), coding region,3'-untranslated region (3'-UTR) and the spliced sites of PAX6gene was PCR-sequencing. All the copy numbers of expressed region were measured by quantitative real-time PCR (qPCR) with Δ Δ Ct relative quantification method of data analysis.Result:The propositus Ⅲ:9had4reported Single nucleotide polymorphism (SNP), rs1806155, rs5790870, rs1806156, rs1806157and rs1806180in the transcript variant3promoter region of PAX6gene, and detected nucleotide substitution g.-1217C>T that was not reported as SNP but still has no segregation with disease phenotype; one SNP rs3026393was detected in the intron12; one SNP rs1506was detected in3'-UTR. Due to the high content of GC in the transcript variant1and2promoter region, the PCR still failed after repeated optimizaiton of the conditions. The copy numbers of each expressed region in three transcript variant of PAX6gene3were two copies.Conclusion:The disease-causing mutation of the ANL family with congenital aniridia is irrelevant to the exon, the junction of exon and intron or copy number variation of PAX6gene, and is irrelevant with the transcript variant3promoter region, but can not rule out whether it is related to the transcript variant1and the transcript variant2promoter region.Chapter3Genetic linkage of a Chinese family with autosomal dominant congenital aniridiaObjective:To determine whether the disease-causing mutation of ANL family with congenital aniridia related to the PAX6gene or not.Methods:Total genomic DNA was isolated from peripheral blood of the two branches of a Chinese family with autosomal dominant congenital aniridia.6microsatellite markers D11S904, D11S1324, D11S914, D11S1776, D11S907andD11S935near the PAX6gene were selected for linkage analysis under LOD value two points linkage analysis, and the haplotype were constitute.Result:In6microsatellite markers, LOD maximum value3.16(θ=0) was obtained at the PAX6gene downstream microsatellite marker D11S1324, and the LOD value of surrounding markers were positive numbers greater than1. The haplotype analysis indicates that the district that6microsatellite markers constitute a segregation phenomenon with disease phenotype in the family.Conclusion:Pathogenic gene mapping of ANL with Congenital Aniridia was near the PAX6gene, and there was a high possibility that it was in the PAX6gene downstream.