Protocol Number: 04-HG-0123

Title:

Bardet-Biedl Syndrome: Phenotype and Metabolic Characteristics

Number:

04-HG-0123

Summary:

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.

-Photographs of the face, hands, feet, body, and genitalia, if the patient agrees.

-Meeting with investigators and a genetic counselor for review of test findings when the studies are completed.

Relatives of patients have a complete medical and family history and physical examination. Blood is drawn for assessment of kidney, liver, heart, and hormonal function and for genetic study and other research purposes. Relatives over 5 years of age may have tests of learning ability and cognition. For younger patients, a parent is asked about the child's development. Relatives meet with investigators and a genetic counselor for review of test findings when the studies are completed.

Sponsoring Institute:

National Human Genome Research Institute (NHGRI)

Recruitment Detail

Type: Active Accrual Of New Subjects

Gender: Male & Female

Referral Letter Required: No

Population Exclusion(s): None

Eligibility Criteria:

INCLUSION/EXCLUSION CRITERIA:

We plan to use the previously published clinical diagnostic criteria for BBS to determine study eligibility of probands. As outlined in that report, we will include patients who present with four of the five primary features and two secondary features.

A patient meets the criteria if they have four primary features OR three primary features and two secondary features:

PRIMARY FEATURES:

Rod-Cone dystrophy

Polydactyly

Obesity

Learning Disabilities

Hypogonadism in males

Renal Anomalies

SECONDARY FEATURES:

Speech disorder/delay

Strabismus, cataracts, astigmatism

Developmental Delay

Poly-uria/dipsia (nephrogenic diabetes insipidus)

Ataxia, poor coordination, imbalance

Spasticity

Diabetes mellitus

Dental crowding/hypodontia

Left ventricular hypertrophy/congenital heart disease

Hepatic fibrosis

Parents and siblings of eligible probands will also be eligible.

Unaffected sibs may be used as controls.

Controls will not be recruited from the general population; instead, results of testing will be compared to data from unaffected siblings or to previously published data obtained from appropriate non-BBS control subjects.

We will allow the inclusion of cognitively impaired adults by obtaining a durable power of attorney (DPA) under the guidelines of NIH Policy 'Consent Process in Research Involving Impaired Human Subjects.'

Under these guidelines (vide supra) we may also include any child (less than 18yr) whose parent or legal guardian is unable to understand the informed consent process or to give consent for his/her child, and children older than 7 yr who are unable to assent to the study.

Special Instructions: Currently Not Provided

Keywords:

Diabetes

Obesity

Retinopathy

Cognition

Metabolism

Dyslipidemia

Insulin Resistance

Hypogonadism

Polydactyly

Recruitment Keywords:

Bardet-Biedl Syndrome

BBS

Conditions:

Bardet-Biedl Syndrome

Investigational Drug(s):

None

Investigational Device(s):

None

Contacts:

Patient Recruitment and Public Liaison Office
Building 61
10 Cloister Court
Bethesda, Maryland 20892-4754
Toll Free: 1-800-411-1222
TTY: 301-594-9774 (local),1-866-411-1010 (toll free)
Fax: 301-480-9793

Electronic Mail:prpl@mail.cc.nih.gov

Citations:

Green JS, et al. The cardinal manifestations of Bardet-Biedl syndrome, a form of Laurence-Moon-Biedl syndrome. N Engl J Med. 1989 Oct 12;321(15):1002-9. PMID: 2779627

Katsanis N, et al. Triallelic inheritance in Bardet-Biedl syndrome, a Mendelian recessive disorder. Science. 2001 Sep21;293(5538):2256-9. PMID: 11567139

Slavotinek AM, et al. Mutation analysis of the MKKS gene in McKusick-Kaufman syndrome and selected Bardet-Biedl syndrome patients. Hum Genet. 2002 Jun;110(6):561-7. Epub 2002 May 09. PMID: 12107442

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