ATXN7-Related Cone-Rod Dystrophy: The Integrated Functional Evaluation of the Cerebellum (CERMOI) Study

Importance

Reliable biomarkers with diagnostic and prognostic values are needed for upcoming gene therapy trials for spinocerebellar ataxias.

Objective

To identify ophthalmological biomarkers in a sample of spinocerebellar ataxia type 7 (SCA7) carriers.

Design, Setting, and Participants

This article presents baseline data from a cross-sectional natural history study conducted in Paris, France, reference centers for rare diseases from May 2020 to April 2021. Data were analyzed from September to December 2022. Fifteen adult ATXN7 pathogenic expansion carriers (9 with preataxia and 6 with ataxia) were included, all with a Scale for the Assessment and Rating of Ataxia (SARA) score of 15 of 40 or lower. Patients were recruited at the Paris Brain Institute, and all contacted patients accepted to participate in the study.

Main Outcomes and Measures

Three visits (baseline, 6 months, and 12 months) were planned, including neurological examination (SARA and Composite Cerebellar Functional Severity Score), ophthalmological examination (best-corrected visual acuity, microperimetry, full-field electroretinogram, optical coherence tomography, and fundus autofluorescence imaging), and neurofilament light chain (NfL) measurements. Here we report the baseline ophthalmic data from the cohort and determine whether there is a correlation between disease scores and ophthalmic results.

Results

Among the 15 included SCA7 carriers (median [range] age, 38 [18-60] years; 8 women and 7 men), 12 displayed cone or cone-rod dystrophy, with the number of CAG repeats correlating with disease severity (ρ, 0.73, 95% CI, 0.34 to 0.90; P < .001). Two patients with cone-rod dystrophy exhibited higher repeat numbers and greater ataxia scores (median [range] SARA score, 9 [7-15]) compared to those with only cone dystrophy (median [range] SARA score, 2 [0-5]). A correlation emerged for outer nuclear layer thickness with SARA score (ρ, -0.88; 95% CI, -0.96 to -0.59; P < .001) and NfL levels (ρ, -0.87; 95% CI, -0.86 to 0.96; P < .001). Moreover, ataxia severity was correlated with visual acuity (ρ: 0.89; 95% CI, 0.68 to 0.96; P < .001) and retinal sensitivity (ρ, -0.88; 95% CI, -0.96 to 0.59; P < .001).

Conclusions and Relevance

In this cross-sectional study, retinal abnormalities were found at preataxic stages of the disease. Most of the carriers presented with cone dystrophy and preserved rod function. The outer nuclear layer thickness correlated with SARA score and plasma NfL levels suggesting nuclear layer thickness to be a biomarker of disease severity. These findings contribute to understanding the dynamics of SCA7-related retinal dystrophy and may help lay the groundwork for future therapeutic intervention monitoring and clinical trials.

Trial Registration

ClinicalTrials.gov Identifier: NCT04288128.

EARLY-ONSET OF FAMILIAL EXUDATIVE VITREORETINOPATHY: Clinical Characteristics, Management, and Outcomes

PURPOSE

To describe the clinical characteristics, management, and outcomes of toddlers (under the age of 3) diagnosed with familial exudative vitreoretinopathy.

METHODS

In this retrospective study, patients diagnosed with familial exudative vitreoretinopathy before the age of 3 were included. Presenting characteristics, genetic testing, management, and outcomes were collected.

RESULTS

A total of 54 patients (108 eyes) with a mean age at diagnosis of 10.9 ± 2.6 months were included. Poor visual behavior (33%) and strabismus (26%) were the most common presenting symptoms, whereas screening only represented 11%. About half of included patients had a severe disease (stages 4 and 5). Genetic testing was positive in 40.7% of patients with 24% having a family history of familial exudative vitreoretinopathy. LRP5 was the most prevalent mutation (54.5%).Surgery was performed in 44.4% of eyes and was successful in 69.8% of cases. Failure exclusively occurred in eyes with severe stages. Among eyes evaluated for visual acuity (72 eyes), most (76.4%) had a vision of hand motion or better.

CONCLUSION

Familial exudative vitreoretinopathy tended to be worse with earlier age at diagnosis, subsequently affecting the prognosis. Surgical intervention was common and primarily included lens-sparing vitrectomy and combined lensectomy and vitrectomy. Surgical success hinged on the stage of the disease.

Preclinical training of future ocular surgeons: a French opinion-based study

PURPOSE

To assess ophthalmology residents satisfaction regarding surgical training during residency in France.

METHODS

A questionnaire consisting of 28 questions was designed and sent to residents of ophthalmology across the 27 French regions.

RESULTS

A total of 30.3% ophthalmology residents in France completed our questionnaire. All French regions participated. They rated 5,27 ± 2.42/10 the global surgical training during residency. They had performed at least one step of any type of ocular surgery for 93.4% of them, while 80.7% had completed at least one full cataract surgery, by the beginning of their second year of residency on average (Paris: 2.59 ± 1.36 semesters; regions: 4.05 ± 1.96 semesters, p < 0.0001). Only 48.9% identified a surgical mentor during their residency, but 82.2% did not clearly identify surgical goals & objectives during their training. Simulation was available for any type of ocular surgery to all residents in the Paris (Île-de-France) region and to 78.1% in other regions (p < 0.005). Residents who accessed drylabs and wetlabs gave a satisfaction score of 7.31 ± 1.89/10 and 6.39 ± 2.15/10 to it respectively. Simulation was a mandatory part of the curriculum for 35.2% of the resident. They commented on on reduced access to subspecialized surgery. They were willing for more access to simulation and surgery on real patients, as well for closer mentoring and clearly defined surgical goals within the curriculum.

CONCLUSION

Ophthalmology residents seemed globally satisfied with their surgical training nationwide, although we observed disparities across region. They largely acknowledged a lack of standard procedures nationwide. They acclaimed simulation during the initial phase of residency, progressively switching towards surgery on real patients. An "operating license" during residency could be a viable way for the resident to demonstrate that they have acquired enough surgical abilities to perform surgery on real patients.