Cornea - ARVO

ARVO 2013 Annual Meeting Abstracts by Scientific Section/Group - CorneaResults: The transduction efficiency of the wild-type TACSTD2gene to the immortalized cell lines was approximately 80%. TER ofthe immortalized cell lines was increased after the transduction of thewild-type TACSTD2 gene. The permeability of fluorescein in theimmortalized cell lines was decreased after the transduction of thewild-type TACSTD2 gene.Conclusions: The findings of this study show that transduction of thewild-type TACSTD2 gene normalizes the disease situation of GDLDcorneas to some extent, thus indicating that gene therapy may proveto be a promising treatment for GDLD.Commercial Relationships: Koji Kitazawa, None; SatoshiKawasaki, None; Keita Aoi, None; Katsuhiko Shinomiya, None;Akira Matsuda, None; Toshinari Funaki, None; MinaNakatsukasa, None; Junji Hamuro, None; Akira Murakami,SEED(Japan) JP4855782 (P), SEED(Japan) JP5132958 (P); ShigeruKinoshita, Senju Pharmaceutical Co (P), Santen Pharmaceutical Co(P), Otsuka Pharmaceutical Co (C), Alcon (R), AMO (R), HOYA (R)Support: H23-Nanchi-Ippan-084 from the Japanese Ministry ofHealth, Labour and Welfare.Program Number: 4560Presentation Time: 12:15 PM - 12:30 PMA Family-based Investigation of the Role of TCF4 TrinucleotideRepeat Expansion in Fuchs Endothelial Corneal Dystrophy(FECD)Keith H. Baratz 1 , Ross A. Aleff 2 , Yi-Ju Li 3 , Malinda L. Butz 4 , SimonG. Gregory 5 , Gordon K. Klintworth 6 , W. Edward Highsmith 4 , NatalieA. Afshari 7 , Eric D. Wieben 2 . 1 Ophthalmology, Mayo Clinic,Rochester, MN; 2 BIochemistry and Molecular Biology, Mayo Clinic,Rochester, MN; 3 Biostatistics and BioInformatics, Center for HumanGenetics, Duke University Medical Center, Durham, NC;4 Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN;5 Medicine, Molecular Genetics and Microbiology, Duke UniversityMedical Center, Durham, NC; 6 Ophthalmology, Duke UniversityMedical Center, Durham, NC; 7 Ophthalmology, University ofCalifornia, San Diego, San Diego, CA.Purpose: Previous studies of unrelated FECD subjects andunaffected controls revealed a strong association between thepresence of more than 50 repeats of the trinucleotide TGC in the thirdintron of the transcription factor 4 (TCF4) gene and the incidence ofFECD. To evaluate the role of this triplet repeat in the inheritance ofthe disease, we examined whether this trinucleotide repeat expansionin TCF4 segregates with the incidence of FECD in families.Methods: The corneas of FECD probands and their family memberswere graded by using a modified Krachmer scale (grade 0 - 6).Leukocyte-derived DNA was evaluated by fluorescence based shorttandem repeat (STR) assays to calculate the TGC repeat length ofboth alleles in all affected and unaffected participants. Southern blotanalysis was used to interrogate the repeat status in all DNA samplesthat had only a single allele by STR analysis. A total of 30participants (33-91 years) from 11 families were included.Results: The size of the trinucleotide repeat in patients with FECDranged between 12 and 89 TGC repeats. Expansion above 50 repeatstracked with the disease in six of eleven families. In one additionalfamily, 2 of 4 participants had FECD and repeat expansions of 59 and62 TGC repeats, one member (48 yrs.) had equivocal disease withexpansion (grade 1; 59 repeats), while the fourth family member (53yrs.) had TGC expansion but no evidence of disease (gr. 0; 59repeats). In the remaining four families, no repeat expansions abovethe 50 repeat threshold for disease association were identified in anyof the seven affected (≥ gr. 2) and one equivocally affected (gr. 1)family members. Among families with expanded TGC repeats, thevariation in repeat size was between 0 and 3 repeats in parent-childtransmission and between 0 and 6 repeats between siblings.Conclusions: Moderate expansions of the TGC repeat in TCF4predicted FECD status in 6 of 11 FECD families. In a subset ofFECD families, there was no expansion of this trinucleotide repeat.Thus, the repeat status may be useful and necessary in stratifyingpatients in further genetic studies of FECD and in studies of diseasepathophysiology using FECD-affected tissue. In this small cohort, theexpansion size varied minimally within families.Commercial Relationships: Keith H. Baratz, Assessing thelikelihood of developing Fuchs Corneal Dystrophy (P); Ross A.Aleff, Mayo Foundation (P); Yi-Ju Li, None; Malinda L. Butz,None; Simon G. Gregory, None; Gordon K. Klintworth, None; W.Edward Highsmith, None; Natalie A. Afshari, None; Eric D.Wieben, Assessing the likelihood of developing Fuchs CornealDystrophy (P)Support: NIH Grant UL1 RR024150; Research to PreventBlindness, N.Y.; and the Mayo FoundationProgram Number: 4561Presentation Time: 12:30 PM - 12:45 PMAGBL1 implicated in the pathogenesis of late-onset FCD andinteracts with TCF4John D. Gottsch 1 , Shivakumar Vasanth 2 , Nicholas Katsanis 2 , S. AmerRiazuddin 1 . 1 Wilmer Eye Institute, Johns Hopkins University Schoolof Medicine, Baltimore, MD; 2 Center for Human Disease Modeling,Duke University Medical Center, Durham, NC.Purpose: Fuchs corneal dystrophy (FCD) is a genetic disorder of thecorneal endothelium and a leading cause of corneal transplantation inthe United States. The following study was undertaken to investigatethe causality of FCD in a large family.Methods: A large familial case of FCD was ascertained with nineaffected and six unaffected individuals in three generations. Agenome-wide linkage scan was completed with an Affymetrix SNPgenotyping array. Two-point Lod scores were calculated and allregions with Lod scores >1 were confirmed by closely-spacedfluorescently-labeled short tandem repeat (STR) markers. Nextgenerationsequencing of captured exons in the critical region wasemployed to identify the causal allele(s) responsible for thephenotype. Immunohistochemical (IHC) analyses were performed oncorneal sections to investigate the expression in the cornealendothelium and a co-immunoprecipitation (Co-IP) approach wasused to investigate protein-protein interactions.Results: The genome-wide linkage analyses identified two causalloci, present on chromosomes 3p and 15q that were confirmed bygenotyping closely-spaced fluorescently-labeled STR markers.Alleles at these loci were not sufficient to independently localize thecausal phenotype; however, taken together alleles at these two locicould explain the causality and the severity associated with thephenotype. Subsequently, we identified a premature termination in acytosolic carboxypeptidase termed CCP4 also known as AGBL1present within the critical interval of 15q. This gene was identifiedpreviously in a serial analysis of gene expression (SAGE) of thecorneal endothelium. The premature termination variant was notpresent in 384 ethnically matched control chromosomes.Subsequently, we identified two independent sporadic cases thatharbored the same premature termination mutation and a secondmissense variation in three unrelated sporadic cases. IHC analysesidentified AGBL1 expression in the corneal endothelium and co-IPexperiments confirmed that AGBL1 and TCF4 proteins can bind.Conclusions: We identify two novel FCD loci and implicate AGBL1in the pathogenesis of late-onset FCD. Our data provides firstevidence of physical interactions between two late-onset FCD genes.©2013, Copyright by the Association for Research in Vision and Ophthalmology, Inc., all rights reserved. Go to iovs.org to access the version of record. For permissionto reproduce any abstract, contact the ARVO Office at arvo@arvo.org.