Figure 1

BBS mutant mice exhibit no obstruction of CSF flow. Sagittal view of the head of a 7 mo.-old wild- type mouse (A) and axial (B) and coronal (C-E) views of Bbs4^−/− mice injected with 2% Evans Blue dye into the lateral ventricle to visualize CSF circulation in vivo. Bbs4^−/− mice exhibit no impediment in CSF intra- or extra-ventricular flow as seen by the presence of dye in the enlarged lateral ventricles, third and fourth ventricles, cisterns and subarachnoid space. Representative T-1 weighted sagittal MRIs show no impediment to CSF flow in BBS mutant mice (F). All MRI images were collected from 6 month-old mice with the exception of 3.5 month-old Bbs1^M390R/M390R mice. CA (cisterna ambiens), CM (cisterna magna), PC (pontine cistern), SAS (subarachnoid space), 3 V (3^rd ventricle), 4 V (4^th ventricle). Bars equal 2 mm (A, B) and 1 mm (C-E).