New Noncoding Base Pair Mutation at the Identical Locus as the Original NCMD/MCDR1 in a Mexican Family, Suggesting a Mutational Hotspot

Purpose

To clinically and molecularly study a newly found family with North Carolina macular dystrophy (NCMD/MCDR1) from Mexico.

Methods

This retrospective study comprised 6 members of a 3-generation Mexican family with NCMD. Clinical ophthalmic examinations, including fundus imaging, spectral-domain optical coherence tomography, electroretinography, and electrooculography, were performed. Genotyping with polymorphic markers in the MCDR1 region was performed to determine haplotypes. Whole-genome sequencing (WGS) was performed followed by variant filtering and copy number variant analysis.

Results

Four subjects from 3 generations were found to have macular abnormalities. The proband presented with lifelong bilateral vision impairment with bilaterally symmetric vitelliform Best disease-like appearing macular lesions. Her 2 children had bilateral large macular coloboma-like malformations, consistent with autosomal dominant NCMD. The 80-year-old mother of the proband had drusen-like lesions consistent with grade 1 NCMD. WGS and subsequent Sanger sequencing found a point mutation at chr6:99593030G>C (hg38) in the noncoding region of the DNase I site thought to be a regulatory element of the retinal transcription factor gene PRDM13. This mutation is the identical site/nucleotide as in the original NCMD family (#765) but is a guanine to cytosine change rather than a guanine to thymine mutation, as found in the original NCMD family.

Conclusions

We report a new noncoding mutation at the same locus (chr6:99593030G>C) involving the same DNase I site regulating the retinal transcription factor gene PRDM13. This suggests that this site, chr6:99593030, is a mutational hotspot.

Closure of Macular Holes With Topical Therapy

Purpose: To report the results of a nonsurgical approach to repair macular holes (MHs). Methods: A retrospective chart review of consecutive patients with MHs from 2018 to 2021 was performed. Topical therapy consisted of a steroidal agent, a nonsteroidal agent, and a carbonic anhydrase inhibitor. Data collected included the size, stage, and duration of the MH; topical agents used and the duration; lens status; and complications. Macular edema was graded on a scale ranging from 0 (no edema) to 4 (large amount of edema) and recorded. Before and after MH closure, the best-corrected visual acuity (BCVA) was measured and converted to logarithm of the minimum angle of resolution (logMAR) notation. Spectral-domain optical coherence tomography was performed. Results: Seven (54%) of the 13 eyes initially treated topically experienced successful MH closure. Small holes (<230 µm) with a better initial BCVA (0.474 logMAR vs 0.796 logMAR) were more likely to respond favorably to topical therapy (mean 121 µm vs 499 µm). In addition, holes with less surrounding edema responded better. All holes not responding to topical therapy were subsequently closed with pars plana vitrectomy å, membrane peeling, and fluid–gas exchange. Conclusions: Topical therapy is a reasonable first-line treatment for MHs, with a better than 50% success rate. This is especially true for small early-onset holes with minimal or no edema. Surgery still had a high success rate after a 1- to 3-month delay while the MH was treated with eyedrops.

North Carolina Macular Dystrophy (NCMD/MCDR1): Long-term follow-up of the original family

PURPOSE

The phenotype of NCMD is highly variable and remains poorly appreciated and understood often causing misdiagnoses in isolated cases. One of the features of NCMD is the general lack of progression despite its original name, "dominant progressive foveal dystrophy", as reported in 1971 by Lefler (HL) et al. The purpose of this study is to report long-term follow-up of this condition.

DESIGN

A systematic, longitudinal and detailed documentation along with imaging of the peripheral retina.

SUBJECTS

We reexamined 27 of the original NCMD family members in an office setting 30-50 years after first being reported.

METHODS

Evaluation of all affected subjects included: best-corrected visual acuity (BCVA), slit lamp and dilated fundus examinations, wide-field fundus and autofluorescent photography and SD-OCT. Blood was collected for DNA extraction, banking and sequencing.

MAIN OUTCOME MEASURES

Best-corrected visual acuity (BCVA), slit lamp and dilated fundus examinations, wide-field fundus and autofluorescent photography and SD-OCT.

RESULTS

The 27 subjects examined were part of the original NCMD family initially reported in 1971. The point mutation (NC_000006.11:g.100040906G>T)(Hg19) in a non-coding region of a DNASE1 hypersensitivity binding site was found in all affected subjects. Nine were affected children of those originally examined 30 - 50 years ago by KS and HL and the remaining 17 subjects (34 eyes) had been examined 30 years previously by KS. Of these 17 subjects (34 eyes), 4/34 (11%) eyes showed worsening of vision with evidence of fibrosis from choroidal neovascular membranes (CNVMs). Fourteen of the 27 patients (51%) showed peripheral retinal drusen, which did not seem to correlate with the macular disease severity.

CONCLUSIONS

Most NCMD patients have stable vision and fundus findings throughout their lives even up to 50 years follow-up. The ones who experienced BCVA decline did so because of apparent evidence of choroidal neovascular membranes (CNVMs). Patients with grade 2 NCMD seem to be more at risk for further/ progressive vision loss due to CNVMs. Intravitreal therapy with vascular endothelial growth factor inhibitors may benefit these patients if treated in a timely fashion. Peripheral retina drusen of varying degrees of severity were found in slightly more than half of the affected subjects and of those, 5 showed the retinal drusen to be autofluorescent.

Best Vitelliform Macular Dystrophy (BVMD) is a phenocopy of North Carolina Macular Dystrophy (NCMD/MCDR1)

PURPOSE

North Carolina Macular Dystrophy (NCMD) and Best Vitelliform Macular Dystrophy (BVMD) are rare autosomal dominant macular dystrophies. Both BVMD and NCMD have markedly variable expressivity. In some individuals, it can be difficult to differentiate between the two disease entities.

METHODS

Clinical findings including fundus photography, fundus autofluorescence (FAF), and spectral domain optical coherence tomography (SD-OCT) were evaluated in 5 individuals with NCMD and 3 with BMD. Electrooculography (EOG) was performed in 2 NCMD subjects. Molecular diagnosis was performed using Sanger DNA sequencing. IRB approval was obtained.

RESULTS

Five NCMD subjects had clinical findings indistinguishable from three of our BVMD subjects. Molecular diagnosis was confirmed in all but one BVMD subject who had an abnormal EOG prior to discovery of the BEST1 gene. Two NCMD subjects had an abnormal EOG with a normal ERG, which has been considered a unique feature of BVMD. SD-OCT in one BVMD subject demonstrated a small lucency/excavation into the choroid similar to that in grade 3 lesions of NCMD. Two NCMD subjects had elevated sub-macular lesions giving a pseudo-vitelliform appearance on OCT similar to BVMD.

CONCLUSION

Best Vitelliform Macular Dystrophy can be a phenocopy of NCMD. There is considerable clinical overlap between NCMD and BVMD, which can cause diagnostic inaccuracies. Our new findings demonstrate that like BVMD, NCMD can also have an abnormal EOG with a normal ERG. The overlapping phenotypes of BVMD with NCMD may provide insights into the mechanisms of the macular changes.

A novel duplication involving PRDM13 in a Turkish family supports its role in North Carolina macular dystrophy (NCMD/MCDR1)

Purpose

To clinically and molecularly investigate a new family with North Carolina macular dystrophy (NCMD) from Turkey, a previously unreported geographic origin for this phenotype.

Methods

Clinical ophthalmic examinations, including fundus imaging and spectral domain-optical coherence tomography (SD-OCT), were performed on eight members of a two-generation non-consanguineous family from southern Turkey. Whole genome sequencing (WGS) was performed on two affected subjects, followed by variant filtering and copy number variant (CNV) analysis. Junction PCR and Sanger sequencing were used to confirm and characterize the duplication involving PRDM13 at the nucleotide level. The underlying mechanism was assessed with in silico analyses.

Results

The proband presented with lifelong bilateral vision impairment and displayed large grade 3 coloboma-like central macular lesions. Five of her six children showed similar macular malformations, consistent with autosomal dominant NCMD. The severity grades in the six affected individuals from two generations are not evenly distributed. CNV analysis of WGS data of the two affected family members, followed by junction PCR and Sanger sequencing, revealed a novel 56.2 kb tandem duplication involving PRDM13 (chr6:99560265-99616492dup, hg38) at the MCDR1 locus. This duplication cosegregates with the NCMD phenotype in the five affected children. No other (likely) pathogenic variants in known inherited retinal disease genes were found in the WGS data. Bioinformatics analyses of the breakpoints suggest a replicative-based repair mechanism underlying the duplication.

Conclusions

We report a novel tandem duplication involving the PRDM13 gene in a family with NCMD from a previously unreported geographic region. The duplication size is the smallest that has been reported thus far and may correlate with the particular phenotype.

Genetics and Age-Related Eye Disease Study Formulation Interaction in Neovascular Age-Related Macular Degeneration

Purpose:

This work aims to determine whether previously defined genotype risk groups interact with Age-Related Eye Disease Study formulation (AREDS-F) use in progression to neovascular age-related macular degeneration (nvAMD).

Methods:

We conducted a case-only study of 265 nvAMD patients. Patients were anonymously genotyped at the complement factor H and age-related maculopathy susceptibility 2 loci and segregated into genotype groups (GTGs) defined by specific combinations of risk alleles. Physicians, who were blind to patients’ GTGs, obtained patients’ AREDS-F use history. The facility performing genetic analysis was blind to the AREDS-F use history. We used logistic analysis to estimate the interaction coefficient between AREDS-F use and GTG 2 vs GTG 3 in a general-population model.

Results:

The odds ratio of numbers of patients reporting prior AREDS-F use to nonuse for GTG 2 vs GTG 3 was 4.18 ( P = .001). Logistic regression, correcting for nongenetic risk factors, gave an estimate of the β for interaction of AREDS-F with genotype of 1.57 ( P = .001). This estimates a corrected odds ratio associated with the effect of interaction of 4.81 between those in GTG 2 compared with those in GTG 3.

Conclusions:

Our data indicate an interaction between GTGs and AREDS-F use that is consistent in size and direction with previously published reports, which had found that using AREDS-F supplements significantly increases the risk of nvAMD for some users and significantly protects other users.

Congenital toxoplasmosis as one phenocopy of North Carolina Macular Dystrophy (NCMD/MCDR1)

Purpose

To highlight the striking similarities between the lesions of congenital toxoplasmosis (CT) and North Carolina Macular Dystrophy (NCMD) using multimodal imaging including spectral domain optical coherence tomography (SD-OCT).

Observations

We are comparing a case report of CT compared to that of NCMD. The case of a 64-year-old man with a lifelong history of decreased vision OD from toxoplasmosis and new onset of central retinal vein occlusion OS. Color fundus photography, spectral domain optical coherence tomography (SD-OCT), and intravenous fluorescein angiography (IVFA) were used as diagnostic imaging tools to demonstrate the similarities and differences between CT and NCMD. In this case, unilateral CT demonstrated a large, excavated, coloboma-like chorioretinal lesion identical to NCMD grade 3. Serology studies were positive for toxoplasmosis. The similarities of CT and NCMD grade 3 using SD-OCT are especially striking.

Conclusion and importance

Lesions of CT and NCMD grade 3 can appear identical on clinical exam and are indistinguishable from one another on SD-OCT. Because CT is a phenocopy of NCMD, many cases of the original NCMD family members had been misdiagnosed as CT. North Carolina Macular Dystrophy may be more common than previously realized and bilateral CT cases should be reexamined along with family members and genetic testing performed. Cases of bilateral CT actually may be NCMD cases. Now that the genetic and molecular mechanisms of NCMD are known, these may provide clues into the pathogenesis of CT.

Long-lasting effects of anti-VEGF/photodynamic combination therapy in the treatment of exudative age-related macular degeneration: a retrospective chart review

Purpose

To examine the potential long-term benefit of an anti-VEGF/photodynamic therapy (PDT) combination on patients treated for wet age-related macular degeneration (AMD).

Methods

A retrospective chart review was conducted on 29 eyes (subjects) from 26 patients (eight male and 18 female) that showed sustained, positive response to combination therapy for exudative AMD for a minimum of 1 year. Collected data included: visual acuity, central retinal thickness, intraocular pressure and history of glaucoma, wet AMD onset and treatment history, concomitant use of anticoagulants and past history or development of cerebrovascular or cardiovascular disease while receiving combination therapy.

Results

Subjects underwent an average of five injections and two PDT treatments in total over 16 months before the choroidal neovascular membrane (CNVM) stabilized and became inactive for at least 1 year. Prior to the effective anti-VEGF/PDT combination therapy the median Snellen visual acuity ranged from 20/200 to 20/250 and presented at no worse than 20/200 at 1 year after treatment. Some subjects were followed for up to 5 years and remained inactive.

Conclusion

Combination therapy can cause long-lasting closure of the CNVM, even with advanced disease resistant to anti-VEGF monotherapy.