summary data were used for downstream analysis. From the total of 47,293 probes, we excluded 30,806 probes called as “absent” (detection score less than 0.95) in >80% arrays to eliminate noise. We retained 16,487 probes representing 15,576 genes for analysis. The data were then normalized using quantile normalization (Bolstad et al. 2003). We performed parallel analysis on both samples and observed similar results. The research has been approved by the United Kingdom National MREC, and written fully informed consent was obtained from all subjects or their parents.
