We also examined the expression of: a) murine orthologues of three genes suggested as positional candidates for PP (Jones et al., 2007) (Abat and Grin2a at 16p13, and Adcy8 at 8q24), b) two genes within 16p13 whose expression correlates with CTGF/CCN2 or NOV/CCN3 expression in developing human brain tissue (Li et al., 2016) (Hba-a1/a2 and Arhgdig), and c) two genes suggested by genomewide association studies as candidates for bipolar disorder (Cacna1c and Odz4/Tenm4)(Harrison, 2016). This evidence concerns the gene ARHGDIG and bipolar disorder.