Table 1. Study characteristics of the discovery and replication samples.
| Cohort | Country | Platform | N | Intelligence measure | Mean age |
|---|---|---|---|---|---|
| Discovery samples (N = 12 441) | |||||
| ALSPAC-Bristol | UK | Illumina HumanHap550 | 5517 | WISC-III | 9 |
| LBC21-Lothians | UK | Illumina 610 Quad | 464 | Moray House Test No. 12 | 11 |
| LBC36-Lothians | UK | Illumina 610 Quad | 947 | Moray House Test No. 12 | 11 |
| QIMR-Brisbane | Australia | Illumina 610 | 1752 | MAB Full-scale IQ | 16 |
| Raine-Western Australia | Australia | Illumina 660 Quad | 936 | g score | 10 |
| TEDS-England/Wales | UK | Affymetrix 6.0 | 2825 | g score | 12 |
| Replication samples (N = 5548) | |||||
| Generation R-Rotterdam | The Netherlands | Illumina 610K | 1442 | SON-R 2,5–7 | 6 |
| NTR-Amsterdam | The Netherlands | Affymetrix | 739 | RAKIT, WISC-R, WISC-R-III, WAIS-III | 13 |
| UMN-Minnesota | USA | Illumina Human660W-Quad | 3367 | WISC-R, WAIS-R | 14 |
Abbreviations: IQ, Intelligence Quotient; QIMR, Queensland Institute of Medical Research.