[Show abstract][Hide abstract] ABSTRACT: Macular Telangiectasia type 2 (MacTel) is a relatively rare macular disease of adult onset presenting with distortions in the visual field and leading to progressive loss of visual acuity. For the purpose of a gene mapping study, several pedigrees were ascertained with multiple affected family members. Seventeen families with a total of 71 individuals (including 45 affected or possibly affected) were recruited at clinical centers in 7 countries under the auspices of the MacTel Project. The disease inheritance was consistent with autosomal dominant segregation with reduced penetrance. Genome-wide linkage analysis was performed, followed by analysis of recombination breakpoints. Linkage analysis identified a single peak with multi-point LOD score of 3.45 on chromosome 1 at 1q41-42 under a dominant model. Recombination mapping defined a minimal candidate region of 15.6 Mb, from 214.32 (rs1579634; 219.96 cM) to 229.92 Mb (rs7542797; 235.07 cM), encompassing the 1q41-42 linkage peak. Sanger sequencing of the top 14 positional candidates genes under the linkage peak revealed no causal variants in these pedigrees.
PLoS ONE 08/2012; 7(8):e24268. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To find the gene(s) responsible for macular telangiectasia type 2 (MacTel) by a candidate-gene screening approach.
Candidate genes were selected based on the following criteria: those known to cause or be associated with diseases with phenotypes similar to MacTel, genes with known function in the retinal vasculature or macular pigment transport, genes that emerged from expression microarray data from mouse models designed to mimic MacTel phenotype characteristics, and genes expressed in the retina that are also related to diabetes or hypertension, which have increased prevalence in MacTel patients. Probands from eight families with at least two affected individuals were screened by direct sequencing of 27 candidate genes. Identified nonsynonymous variants were analyzed to determine whether they co-segregate with the disease in families. Allele frequencies were determined by TaqMan analysis of the large MacTel and control cohorts.
We identified 23 nonsynonymous variants in 27 candidate genes in at least one proband. Of these, eight were known single nucleotide polymorphisms (SNPs) with allele frequencies of >0.05; these variants were excluded from further analyses. Three previously unidentified missense variants, three missense variants with reported disease association, and five rare variants were analyzed for segregation and/or allele frequencies. No variant fulfilled the criteria of being causal for MacTel. A missense mutation, p.Pro33Ser in frizzled homolog (Drosophila) 4 (FZD4), previously suggested as a disease-causing variant in familial exudative vitreoretinopathy, was determined to be a rare benign polymorphism.
We have ruled out the exons and flanking intronic regions in 27 candidate genes as harboring causal mutations for MacTel.
[Show abstract][Hide abstract] ABSTRACT: Inflammation may play an important role in the pathogenesis of diabetic macular edema, a major cause of vision loss in persons with diabetes. The purpose of this study was to evaluate combined antiinflammatory therapy and laser approaches for treating patients with diabetic macular edema.
In this prospective, factorial, randomized, multicenter trial, we compared cyclo-oxygenase-2 inhibitor (celecoxib) with placebo and diode grid laser with standard Early Treatment Diabetic Retinopathy Study focal laser treatment in 86 participants with diabetic macular edema. The primary outcome is change in visual acuity of > or = 15 letters from baseline, and the secondary outcomes include a 50% reduction in the retinal thickening of diabetic macular edema measured by optical coherence tomography and a 50% reduction in leakage severity on fluorescein angiography.
Visual acuity and retinal thickening data from >2 years of follow-up did not show evidence of differences between the medical and laser treatments. However, participants assigned to the celecoxib group were more likely to have a reduction in fluorescein leakage when compared with the placebo group (odds ratio = 3.6; P < 0.01).
This short-term study did not find large visual function benefits of treatment with celecoxib or diode laser compared with those of standard laser treatment. A suggestive effect of celecoxib in reducing fluorescein leakage was observed.
[Show abstract][Hide abstract] ABSTRACT: To describe the baseline characteristics of a large international cohort of patients with macular telangiectasia type 2 (MacTel Type 2) in anticipation of a longitudinal natural history study to evaluate structural and functional changes, identify potential risk factors and related outcomes.
Images including fundus photographs, fluorescein angiograms, optical coherence tomography and fundus autofluorescence were collected. A grading system for MacTel type 2 was developed by the central reading center to evaluate lesion characteristics. Relationships between lesion characteristics and visual acuity were evaluated.
A total of 310 participants have been enrolled in the study. The mean time since diagnosis was 3 years (range 0 to 25 years). The mean age at the baseline examination was 61 +/- 9 years. The mean visual acuity in the better eye was approximately 20/32 Snellen equivalents and approximately 20/50 in the worse eye. The visual acuity in the better eye of half of the participants was 20/32 or better. We found some relationships between visual acuity and lesions characteristic of MacTel Type 2.
This is the first large-scale study of patients with MacTel Type 2. More than half of the patients had 20/32 or better vision in their better eye, which is a sign that decreased function in these participants may not be reflected in central visual acuity. These findings highlight the limitation of using visual acuity measurements as a measure of function and as an outcome measure in potential clinical trials in patients with MacTel Type 2.
[Show abstract][Hide abstract] ABSTRACT: To describe vision-targeted health-related quality of life (HR-QOL), measured with the National Eye Institute Visual Functioning Questionnaire (NEI-VFQ-25) in a cohort of patients with macular telangiectasia (MacTel) type 2 and to evaluate the relationship between visual acuity and NEI-VFQ-25 scores.
This was an analysis of cross-sectional baseline data from a longitudinal natural history study. Patients with MacTel type 2 were enrolled in the Natural History Study of The Macular Telangiectasia Project (The MacTel Project). NEI-VFQ-25 were completed at enrollment. Linear correlation and regression analyses were used to relate baseline NEI-VFQ-25 overall and subscale scores to visual acuity.
Participants reported lower vision-related functioning measured by the NEI-VFQ-25 in most of the domains measured by the NEI VFQ compared with that of a normal reference group (P < 0.001 for all domains except color vision). Visual acuity was found to be associated with the NEI-VFQ-25 in many of the domains measuring degree of difficulty with common visual activities.
This is the first cross-sectional cohort study to assess vision targeted HR-QOL in patients with MacTel type 2. Patients with MacTel type 2 reported markedly reduced visual functioning compared to reports of a normal reference group. These findings provide support to the use of the NEI-VFQ-25 in patients with MacTel type 2 to measure the effect of disease and potential therapies on vision-targeted HR-QOL.