A significantly reduced cardinal vein and dorsal aorta blood flow velocity (Fig. 2C, P<0.0001; Fig. S8C, P<0.0062; Movies 3 and 4) was measured in heterozygous kcnj8+/V65M larvae, and can be associated with low blood pressure and diminished vascular tone reported in CS patients (Levin et al., 2016). Here, KCNJ8 is linked to Cowden syndrome 1.