PMC4039415_01
Electroretinography and S-Cone ERG findings in case 2. A: ERG findings in case 2. ERG shows severely reduced rod specific responses, response to standard flash was delayed with low amplitude waveform under photopic and scotopic conditions, the 30 Hz flicker was delayed and of lower amplitude. B: S-Cone ERG with blue flash and orange background showing abnormally large, delayed, simplified waveform as enhanced S cone ERG responses.
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The responses to long duration stimulus using a blue flash with orange background (S-cone ERG response) showed an abnormally large delayed waveform typical of the enhanced S-cone response (Figure 4A,B).
Chromatogram representing the p.Asp406Gly mutation in the NR2E3 gene. A: p.Asp406Gly mutation in the homozygous state. B: p.Asp406Gly mutation in the heterozygous state. C: Wild type. The underline marks the mutated codon. The arrow indicates the position of the mutation.
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The p.D406G change was detected in the homozygous state in the proband's brother (affected) and in the heterozygous state in eight unaffected family members (Figure 5; Table 1).
Evolutionary conservation of p.Asp406Gly (D406G) mutation in different species. Amino acid residues highly conserved in all species are indicated by asterisk, and lower identity are shown using colon. Red color box indicate NR2E3 mutations analyzed in this study.
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The identified novel p.D406G homozygous mutation was evolutionarily highly conserved in different species (Figure 6).