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IMPG2-related maculopathy

Birtel, Johannes; Caswell, Richard; De Silva, Samantha R; Herrmann, Philipp; Rehman, Salwah; Lotery, Andrew J; Mahroo, Omar A; ... Issa, Peter Charbel; + view all (2023) IMPG2-related maculopathy. American Journal of Ophthalmology 10.1016/j.ajo.2023.10.002. (In press).

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Purpose: To investigate the phenotype, variability and penetrance of IMPG2-related maculopathy. // Design: Retrospective observational case series. // Methods: Clinical evaluation, multimodal retinal imaging, genetic testing, and molecular modeling. // Results: Twenty-five individuals with a mono-allelic IMPG2 variant were included, 5 of whom were relatives of patients with IMPG2-associated retinitis pigmentosa. In 17 individuals (median age, 52 years; range, 20-72 years), a distinct maculopathy was present and included foveal elevation with or without subretinal vitelliform material or focal atrophy of the retinal pigment epithelium. Best corrected visual acuity (BCVA) was ≥ 20/50 in the better eye (n=15) and 5 patients were asymptomatic. Longitudinal observation (n=8, up to 19 years) demonstrated stable maculopathy (n=3), partial/complete resorption (n=4) or increase (n=1) of the subretinal material, with overall stable vision (n=6). The remaining 8 individuals (median age, 58 years; range, 43-83 years; BCVA ≥ 20/25) showed no manifest maculopathy and were identified through segregation analysis. All 8 were asymptomatic, with minimal foveal changes observed on optical coherence tomography in 3 cases. Eighteen different variants were detected, 11 of them truncating. Molecular modeling of five missense variants, c.727G>C, c.1124C>A, c.2816T>A, c.3047T>C and c.3193G>A supported the hypothesis that these have a loss-of-function effect. // Conclusions: Mono-allelic IMPG2 variants may result in haplo-insufficiency manifesting as a maculopathy with variable penetrance and expressivity. Family members of patients with IMPG2-related retinitis pigmentosa may present with vitelliform lesions. The maculopathy often remains limited to the fovea and is usually associated with moderate visual impairment.

Type: Article
Title: IMPG2-related maculopathy
Location: United States
DOI: 10.1016/j.ajo.2023.10.002
Publisher version: https://doi.org/10.1016/j.ajo.2023.10.002
Language: English
Additional information: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions.
Keywords: Vitelliform; dystrophy; IMPG2; macular dystrophy; Fundus Autofluorescence; Optical, Coherence Tomography; Phenotype; penetrance
UCL classification: UCL
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > Institute of Ophthalmology
URI: https://discovery.ucl.ac.uk/id/eprint/10179329
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