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Bardet-Biedl Syndrome: Phenotype and Metabolic Characteristics

This study is currently Recruiting

June 2011 By National Institutes of Health Clinical Center (CC)

First Recieved on February 18, 2004

Last Updated on July 20, 2011

Sponsor: National Human Genome Research Institute (NHGRI)
Information provided by: National Institutes of Health Clinical Center (CC)
Identifier: NCT00078091


This study will evaluate patients with a rare inherited condition called Bardet-Biedl syndrome . The purpose of the study is to learn more about the genetics and clinical characteristics of this disorder. Patients may have the following problems: polydactyly (extra fingers and toes); retinal dystrophy (changes in the retina that may lead to vision problems, including blindness); obesity and diabetes (overweight and high blood sugar due to failure of body organs to respond to insulin); cognitive dysfunction (difficulties with learning and understanding); hypogenitalism (decreased functioning of the ovaries in women and the testes in men); kidney anomalies (changes in the structure or function of the kidneys); heart disease; and hepatic fibrosis (liver disease). Patients with Bardet-Biedl syndrome may be eligible for this study. First-degree relatives will also be enrolled for certain tests and procedures. Candidates are screened with a review of their medical records, laboratory tests, and x-rays. Patients in this study undergo the following tests and procedures: - Medical and family history and physical examination, including body measurements. - Blood tests to evaluation kidney, liver, heart, and hormonal function, and for genetic studies and other research purposes. - Dual emission x-ray absorptiometry (DEXA) scan to measure the amount of total body fat. For this test, the subject lies on a table for scanning with low-dose X-rays. - Computed tomography (in adults) of the abdomen to measure abdominal fat. CT uses a small amount of radiation to obtain images of internal body structures. - Magnetic resonance imaging (in children) of the abdomen to measure abdominal fat. MRI uses a magnetic field and radio waves to obtain images of internal body structures. - Oral glucose tolerance tests to measure blood glucose and insulin levels. For this test, the patient drinks a glucose (sugar) solution. Blood samples are drawn through an IV catheter before the test begins and at 1, 2, and 3 hours after drinking the solution. - Complete eye examination to look for retinal changes and to assess vision, and, if medically needed, an examination of the ear, nose, and throat to check for hearing and breathing abnormalities. - Tests of learning ability in patients over 5 years of age. For younger patients, a parent is asked about the child's development. - Ultrasound study of the ovaries and uterus in females and of the testes in males. - Photograp...

Study Type: Observational
Study Design: N/A


Ages Eligible for Study:N/A
Genders Eligible for Study:Both
Accepts Healthy Volunteers:No

- 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.



  • National Institutes of Health Clinical Center, 9000 Rockville Pike

    Bethesda, Maryland 20892 United States

Conditions related to this trial:

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