Because cognitive dysfunction is known to be a component of BBS, some patients with impaired cognition and understanding may be evaluated under this protocol. If the investigators believe that an adult patient may not be competent to give informed consent to participate, or does not understand the consent document and the procedures of the study, that patient may be excluded from participation. We may request that the patient and accompanying caregiver also be interviewed by an independent ethics panel to confirm that he or she is competent to give consent and to participate if the team feels this would be useful.