Genetics and Clinical Characteristics of Bardet-Biedl Syndrome

• INCLUSION CRITERIA:

We are using the previously published clinical diagnostic criteria for BBS(21) to determine study eligibility of probands. As outlined in that report, we are including patients who present with four of the five primary features or three primary features and two secondary features. Parents are also enrolled for genetic studies. We are not enrolling unaffected siblings or recruiting control subjects, instead, results of testing are being compared to previously published data obtained from appropriate non-BBS control subjects.

The initial determination of eligibility is made by review of prior clinical records. Some patients are not characterized in sufficient detail to know if the person meets the clinical criteria, yet we may suspect the diagnosis. In those cases, the subjects are brought to NIH and undergo clinically appropriate testing to make the diagnosis. If that clinical testing does not confirm the diagnosis, the patient or parents are given appropriate clinical counseling and returned to the care of their personal physician. If features later develop that allow the diagnosis to be made, they may re-enroll and undergo further evaluation.

Our study population includes patients of all ages and ethnic groups, and both genders. The inclusion of children is essential to a research study that is correlating genotype with phenotype, and is attempting an early identification of metabolic abnormalities that may be best treated at an early age. Many of the age-dependent manifestations of BBS develop during childhood and the average age of diagnosis is 9.2 years. Pregnant women and children under the age of 5 yr do not undergo invasive research procedures (i.e. phlebotomy) or procedures involving ionizing radiation (i.e. X-rays or DEXA scans) unless that procedure would be performed as part of standard medical care.

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.

EXCLUSION CRITERIA:

Neither healthy volunteers unrelated to an affected patient nor lab personnel will be enrolled.

We will make efforts to obtain consent from all parents/guardians of minor subjects (i.e. we would not allow a single parent to consent a child when both parents have parental rights). If a single parent or guardian has sole custody/legal responsibility for a child (e.g., a divorce with full custody to one parent or one parent is deceased), we will accept consent from one parent.

Both mothers and fathers of children with BBS (who are also typically enrolled in our protocol, as described above) are eligible to participate in the interview portion of the study. We hypothesize that mothers and fathers will, as groups, have slightly different experiences with coping with courtesy stigma, although a couple may have convergent beliefs, coping mechanisms, and experiences. As such, we predict that we will initially conduct interviews with both parents of the same proband (assuming both parents are interested in participating), although we may target either mothers or fathers only following interim analysis of the interview transcripts.