Systematic study of ophthalmological findings in 10 patients with PEX1-mediated Zellweger spectrum disorder

ABSTRACT

Purpose

This cross-sectional study describes the ophthalmological and general phenotype of 10 patients from six different families with a comparatively mild form of Zellweger spectrum disorder (ZSD), a rare peroxisomal disorder.

Methods

Ophthalmological assessment included best-corrected visual acuity (BCVA), perimetry, microperimetry, ophthalmoscopy, fundus photography, spectral-domain optical coherence tomography (SD-OCT), and fundus autofluorescence (FAF) imaging. Medical records were reviewed for medical history and systemic manifestations of ZSD.

Results

Nine patients were homozygous for c.2528 G > A (p.Gly843Asp) variants in PEX1 and one patient was compound heterozygous for c.2528 G>A (p.Gly843Asp) and c.2097_2098insT (p.Ile700TyrfsTer42) in PEX1. Median age was 22.6 years (interquartile range (IQR): 15.9 – 29.9 years) at the most recent examination, with a median symptom duration of 22.1 years. Symptom onset was variable with presentations of hearing loss (n = 7) or nyctalopia/reduced visual acuity (n = 3) at a median age of 6 months (IQR: 1.9–8.3 months). BCVA (median of 0.8 logMAR; IQR: 0.6–0.9 logMAR) remained stable over 10.8 years and all patients were hyperopic. Fundus examination revealed a variable retinitis pigmentosa (RP)-like phenotype with rounded hyperpigmentations as most prominent feature in six out of nine patients. Electroretinography, visual field measurements, and microperimetry further established the RP-like phenotype. Multimodal imaging revealed significant intraretinal fluid cavities on SD-OCT and a remarkable pattern of hyperautofluorescent abnormalities on FAF in all patients.

Conclusion

This study highlights the ophthalmological phenotype resembling RP with moderate to severe visual impairment in patients with mild ZSD. These findings can aid ophthalmologists in diagnosing, counselling, and managing patients with mild ZSD.

KEYWORDS:

• Zellweger spectrum disorder
• syndromic retinitis pigmentosa
• fundus autofluorescence
• hyperautofluorescent deposits

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/13816810.2024.2330389.

Additional information

Funding

This research is supported by a grant from Stichting Steunfonds UitZicht (specifically by Algemene Nederlandse Vereniging ter Voorkoming van Blindheid (ANVVB), Landelijke Stichting voor Blinden en Slechtzienden (LSBS), and the Oogfonds) and Stichting Retina Fonds. These funds had no role in the design or conduct of this research.