Finally, whole-exome sequencing (WES) followed by targeted genotyping revealed that the minor A allele of the synonymous SNP rs941909 (G/A) located in exon 1 of LBX1 perfectly segregated with attention-deficit/hyperactivity disorder (ADHD) in an extended, high-density pedigree previously reported [28]. Here, LBX1 is linked to attention deficit-hyperactivity disorder.