A total of 16 patients (26%) were found to have a cone or cone-rod dystrophy, but it appears to be distributed evenly between BBS subtypes (3/15 BBS1, 2/3 BBS2, 3/3 BBS3, 1/5 BBS9, 5/20 BBS10, and 2/3 BBS12). This evidence concerns the gene ARL6 and cone-rod dystrophy.