Fluorescent allele-specific PCR genotyping assays were designed for the MCPH1 variants (KASPar; LGC Genomics, Hoddesdon, UK). Genotyping was performed on a LightCycler 480 Real-Time PCR System (Roche Diagnostics, Burgess Hill, UK) in BPD, SCZ, and control samples. Validation of the genotypes in heterozygote individuals was performed with DNA sequencing (3730xl DNA Analyzer, Applied Biosystems, UK). Genotyping assays were validated by including DNA samples that carried the alternate allele for each variant tested on all of the genotyping plates. The assay for rs61749465 was validated by the inclusion of DNA from a BPD subject known to be heterozygous for the variant from whole genome sequence data generated in a subset of the UCL BPD cohort [Fiorentino and others 2015 (link)] and the assay for rs199422124 was validated using DNA from a cDNA clone carrying the variant allele (see below). Data were analyzed to confirm Hardy-Weinberg equilibrium and tests of allelic association were performed using a Fisher’s exact test. A cut-off significance value of P < 0.05 was used.