Exome sequencing was performed on patient and both parents using the Agilent SureSelectXT HumanAllExon V4 (50 Mb) (Agilent Technologies). Amplified Pre-capture libraries (750 ng) were concentrated in 3 ml and hybridized to the target specific baits (SureSelectXT Human All Exon V4; Agilent Technologies) according to the manufacturer's recommendations. Captured libraries were pooled in pairs and paired-end sequenced on one lane of the Illumina HiSeq 2000 at the Stanford Center for Genomics and Personalized Medicine.