Fig. 1

Analysis of benign choroidal nevi. a Duplex analysis of CYSLTR2 p.L129Q mutation in choroidal nevus 11C using digital PCR. The 2D plot at the left illustrates that no droplets are positive for CYSLTR2 mutant alleles on channel 1 (FAM labelled, in blue) while CYSLTR2 wild-type alleles are abundantly detected on channel 2 (HEX labelled, in green). Empty droplets (in grey) do not contain the CYSLTR2 target amplicon. At the right side the calculated mutant allele fraction with 95% confidence interval confirms the absence of mutant alleles. b Similar analysis for CYSLTR2 p.L129Q mutation in nevus 12B, with detectable mutant alleles on channel 1 (FAM labelled, in blue). Double-positive droplets (in orange) contain both a mutant and wild-type allele. The mutant allele fraction is calculated to be 18.4%. c Upper panel: in-eye image showing nevus 12B as a dark choroidal lesion, with arrow indicating the eye cup. Lower panel: H&E staining showing the nevus as highly pigmented lesion in the choroid. RPE = retinal pigment epithelium, bv = blood vessel