MKKS and Brain atrophy: While patients did not display general brain atrophy in a MRI study (BBS 1,497,830 mm3; controls 1,543,205 mm3; p = 0.2, [53]), we observed brain volume reduction of 12% in Bbs8−/− mice and also olfactory deficits, while Bbs6−/− mice neither had deficits in olfaction nor showed brain atrophy at eight weeks.