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Comment
. 2024 Apr 1;142(4):301-308.
doi: 10.1001/jamaophthalmol.2024.0001.

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

Marco Nassisi  1   2 , Giulia Coarelli  3   4 , Benoit Blanchard  2 , Charlotte Dubec-Fleury  3   4 , Karima Drine  2 , Nicolas Kitic  2 , Serge Sancho  2 , Rania Hilab  3   4 , Sophie Tezenas du Montcel  3   4 , Candice Junge  5 , Roger Lane  5 , H Moore Arnold  6 , Alexandra Durr  3   4 , Isabelle Audo  1   2
Affiliations
Comment

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

Marco Nassisi et al. JAMA Ophthalmol. .

Abstract

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.

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Conflict of interest statement

Conflict of Interest Disclosures: Dr Tezenas du Montcel reported consulting for Biogen outside the submitted work. Dr Junge is an employee at Ionis Pharmaceuticals. Dr Lane reported that Ionis contributed funds to this study and has an interest in developing a disease-modifying therapeutic for SCA7 during the conduct of the study and is an employee at Roger Michael Lane. Prof Durr reported grants from Biogen during the conduct of the study. Prof Audo reported grants from Inserm during the conduct of the study. No other disclosures were reported.

Figures

Figure 1.
Figure 1.. Distribution of Age, Number of CAG Repeats, and Scale for the Assessment and Rating of Ataxia (SARA) Score Based on Full-Field Electroretinography Alterations
Figure 2.
Figure 2.. Correlations Between the Scale for the Assessment and Rating of Ataxia (SARA) Score and Best-Corrected Visual Acuity (BCVA), Retinal Sensitivity on Microperimetry, and Outer Nuclear Layer Thickness on Optical Coherence Tomography
ETDRS indicates Early Treatment Diabetic Retinopathy Study.
See this image and copyright information in PMC

Comment on

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