Genotyping was performed using the SureSelect XT Custom Capture (Agilent). Multiplexing was achieved using TruSeq adapters (Illumina); samples were pooled prior to the capture and amplified post-capture using TruSeq PCR primers (Illumina). Blocking reagents were replaced with water to avoid cross-reactivity. Sequencing was performed using 50-bp paired-end reads (Illumina HiSeq 2000). Reads were aligned to the reference human genome (hg19) using BWA (Li and Durbin 2009 (link)). Genes were sequenced to an average coverage of 200× with 85% of the target sequenced to least at 50×. Genotypes were determined using the Genome Analysis Toolkit (GATK) (McKenna et al. 2010 (link)) “Better” protocol. Only high-confidence (quality score >100) variants predicted to have high or moderate severity and not reported in dbSNP (v129) were considered.