Background
Occult Macular Dystrophy (OMD), primarily caused by retinitis pigmentosa 1-like 1 (
RP1L1
) variants, is a complex retinal disease characterised by progressive vision loss and a normal fundus appearance. This study aims to investigate the diverse phenotypic expressions and genotypic correlations of OMD in Chinese patients, including a rare case of Vitelliform Macular Dystrophy (VMD) associated with
RP1L1
.
Methods
We analysed seven OMD patients and one VMD patient, all with heterozygous pathogenic
RP1L1
variants. Clinical assessments included Best Corrected Visual Acuity (BCVA), visual field testing, Spectral Domain Optical Coherence Tomography (SD-OCT), multifocal Electroretinograms (mfERGs), and microperimetry. Next-generation sequencing was utilised for genetic analysis.
Results
The OMD patients displayed a range of phenotypic variability. Most (5 out of 7) had the
RP1L1
variant c.133 C > T; p.R45W, associated with central vision loss and specific patterns in SD-OCT and mfERG. Two patients exhibited different
RP1L1
variants (c.3599G > T; p.G1200V and c.2880G > C; p.W960C), presenting milder phenotypes. SD-OCT revealed photoreceptor layer changes, with most patients showing decreased mfERG responses in the central rings. Interestingly, a unique case of VMD linked to the
RP1L1
variant was observed, distinct from traditional OMD presentations.
Conclusions
This study highlights the phenotypic diversity within OMD and the broader spectrum of
RP1L1
-associated macular dystrophies, including a novel association with VMD. The findings emphasise the complexity of
RP1L1
variants in determining clinical manifestations, underscoring the need for comprehensive genetic and clinical evaluations in macular dystrophies.
Supplementary Information
The online version contains supplementary material available at 10.1186/s12886-024-03591-7.
