Table 1.
Mean (SD) amplitudes for standard ERG parameters for participants grouped by number of risk alleles
| Stimulus | Response component | Mean (SD) amplitudes, µV | P value (mixed model) | ||
|---|---|---|---|---|---|
| No risk alleles (group 0), n = 37 | One risk allele (group 1), n = 101 |
Two risk alleles (group 2), n = 48 |
|||
| DA 0.01 (dim flash) | b-wave | 197.7 (38.8) | 187.1 (39) | 175.6 (46.4) | 0.078 |
| DA 3 (standard flash) | a-wave | 150.1 (35.2) | 145.5 (28.9) | 138.0 (34.1) | 0.172 |
| b-wave | 264.7 (50.6) | 265.2 (52.5) | 251.2 (67.4) | 0.409 | |
| DA 10 (bright flash) | a-wave | 184.4 (41) | 171.9 (34.6) | 168.7 (35.5) | 0.054 |
| b-wave | 286.7 (63) | 275.5 (56.2) | 267.3 (61.4) | 0.143 | |
| LA 30-Hz flicker | Peak | 72.4 (19.8) | 71.4 (6.6) | 63.6 (25) | 0.267 |
| LA 3 (standard flash) | a-wave | 24.0 (16.3) | 22.4 (5.4) | 20.5 (23.8) | 0.010* |
| b-wave | 102.5 (1.7) | 97.3 (0.7) | 87.4 (1.4) | 0.036* | |
DA refers to stimuli delivered in the dark following 20 min of dark adaptation; LA refers to stimuli delivered in the presence of the standard white photopic background following 10 min of light adaptation. P values in the final column are from a mixed linear model including all participants, using allelic dosage as a predictor and ERG parameters as outcomes, and adjusting for age, sex, and relatedness between individuals. *P < 0.05.