National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Bardet-Biedl syndrome

Bardet-Biedl syndrome (BBS) is an inherited condition that affects many parts of the body. People with this syndrome have progressive visual impairment due to cone-rod dystrophy; extra fingers or toes (polydactyly); truncal obesity; decreased function of the male gonads (hypogonadism); kidney abnormalities; and learning difficulties.[1] Mutations in many genes are known to cause Bardet-Biedl syndrome and inheritance is usually autosomal recessive.[2][3] Treatment depends on the symptoms present in each person.
Last updated: 8/27/2018
Bardet-Biedl syndrome (BBS) affects many parts of the body. Signs and symptoms can vary among affected individuals, even within the same family. The major features include:[4][5][6]
  • Progressive vision loss due to deterioration of the retina. This usually begins in mid-childhood with problems with night vision, followed by the development of blind spots in peripheral vision. Blind spots become bigger with time and eventually merge to produce tunnel vision. Most individuals also develop blurred central vision and become legally blind by adolescence or early adulthood (over 90% of cases).
  • Extra finger next to the pinky (postaxial polydactyly)
  • Kidney problems (polycystic kidneys)
  • Obesity that develops around 2-3 years of age
  • Abnormalities of the genitalia and infertility due to hypogonadism
  • Learning disorders

BBS may also be associated with other features, including:[6][5][4]

  • Diabetes
  • High blood pressure
  • Heart defects
  • Bowel disease (Hirschsprung disease)
  • Neurological problems resulting in gait and coordination impairment
  • Speech and language problems
  • Behavioral disorders
  • Distinctive facial appearance
  • Dental abnormalities
Last updated: 9/18/2017

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Showing of 25 |
Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Abnormal electroretinogram 0000512
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific
Mental-retardation
[ more ] 		0001249
Multicystic kidney dysplasia 0000003
Obesity
Having too much body fat
0001513
Pigmentary retinopathy 0000580
Postaxial hand polydactyly
Extra little finger
Extra pinkie finger
Extra pinky finger
[ more ] 		0001162
30%-79% of people have these symptoms
Hypertension 0000822
Hypogonadism
Decreased activity of gonads
0000135
Hypoplasia of penis
Underdeveloped penis
0008736
Hypoplasia of the ovary
Underdeveloped ovary
0008724
Nystagmus
Involuntary, rapid, rhythmic eye movements
0000639
Short stature
Decreased body height
Small stature
[ more ] 		0004322
5%-29% of people have these symptoms
Cryptorchidism
Undescended testes
Undescended testis
[ more ] 		0000028
Downslanted palpebral fissures
Downward slanting of the opening between the eyelids
0000494
Finger syndactyly 0006101
Generalized hirsutism
Excessive hairiness over body
0002230
Hearing impairment
Deafness
Hearing defect
[ more ] 		0000365
Hepatic fibrosis 0001395
Low-set, posteriorly rotated ears 0000368
Medial flaring of the eyebrow 0010747
Nephrotic syndrome 0000100
Neurological speech impairment
Speech disorder
Speech impairment
Speech impediment
[ more ] 		0002167
Prominent nasal bridge
Elevated nasal bridge
High nasal bridge
Prominent bridge of nose
Prominent nasal root
Protruding bridge of nose
Protruding nasal bridge
[ more ] 		0000426
Short neck
Decreased length of neck
0000470
Skeletal muscle atrophy
Muscle degeneration
Muscle wasting
[ more ] 		0003202
Showing of 25 |
Last updated: 7/1/2020
BBS has an autosomal recessive pattern of inheritance.[2] This means that to have the syndrome, a person must have a mutation in both copies of the responsible gene in each cell. People with BBS inherit one mutated copy of the gene from each parent, who is referred to as a carrier. Carriers of an autosomal recessive condition typically do not have any signs or symptoms (they are unaffected). When 2 carriers of an autosomal recessive condition have children, each child has a:
  • 25% chance to be affected
  • 50% chance to be an unaffected carrier like each parent
  • 25% chance to be unaffected and not a carrier
Some cases of BBS (fewer than 10%) appear to require the presence of at least three mutations for a person to have features of the condition. This is known as triallelic inheritance.[2] In these cases, in addition to inheriting a mutation in the same gene from each parent, a child also needs to have at least one more mutation in another gene to be affected.
Last updated: 9/18/2017

Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.
There is no cure for Bardet-Biedl syndrome. Treatment generally focuses on the specific signs and symptoms in each individual:
  • While there is no therapy for the progressive vision loss, early evaluation by a specialist can help to provide vision aids and mobility training. Additionally, education of affected children should include planning for future blindness.
  • Management of obesity may include education, diet, exercise, and behavioral therapies beginning at an early age. Complications of obesity such as abnormally high cholesterol and diabetes mellitus are usually treated as they are in the general population.
  • Management of intellectual disability includes early intervention, special education and speech therapy as needed. Many affected adults are able to develop independent living skills.
  • Although kidney transplants have been successful, the immunosuppressants used after a transplant may contribute to obesity. Affected individuals may also need surgery for polydactyly (extra fingers and/or toes) or genital abnormalities.
  • As children approach puberty, hormone levels should be monitored to determine if hormone replacement therapy is necessary. Additionally, it should not be assumed that affected individuals are infertile - so contraception advice should be offered.[7]
Last updated: 9/18/2017

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • ClinicalTrials.gov lists trials that are related to Bardet-Biedl syndrome. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

    Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.

Patient Registry

  • A registry supports research by collecting of information about patients that share something in common, such as being diagnosed with Bardet-Biedl syndrome. The type of data collected can vary from registry to registry and is based on the goals and purpose of that registry. Some registries collect contact information while others collect more detailed medical information. Learn more about registries.

    Registries for Bardet-Biedl syndrome:
    The Clinical Registry Investigating Bardet-Biedl Syndrome (CRIBBS)
     

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

Social Networking Websites

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • Genetics Home Reference (GHR) contains information on Bardet-Biedl syndrome. This website is maintained by the National Library of Medicine.
  • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

In-Depth Information

  • GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) lists the subtypes and associated genes for Bardet-Biedl syndrome in a table called Phenotypic Series. Each entry in OMIM includes a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine.
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Bardet-Biedl syndrome. Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know. Submit a new question

  • Can men with Bardet-Biedl syndrome father children? See answer

  • My question is about a student with Bardet-Biedel syndrome who has behavior problems. Is this common? What should we do if the behavior problems continue? See answer

  • My mother is almost blind. Her diagnosis is Bardet-Biedl syndrome. She has no other symptoms besides being almost blind. Is there any cure or treatment for Bardet-Biedl syndrome anywhere in the world? Thank you very much. See answer

  • What about siblings of people with Bardet-Biedl syndrome? See answer


  1. Bardet Biedl Syndrome. National Organization for Rare Disorders. 2007; http://www.rarediseases.org/rare-disease-information/rare-diseases/byID/988/viewAbstract.
  2. Forsythe E, Beales PL. Bardet-Biedl Syndrome. GeneReviews. 2015; http://www.ncbi.nlm.nih.gov/books/NBK1363/.
  3. Weihbrecht K, Goar WA, Pak T, et al. Keeping an Eye on Bardet-Biedl Syndrome: A Comprehensive Review of the Role of Bardet-Biedl Syndrome Genes in the Eye. Med Res Arch. September, 2017; 5(9):https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5814251/.
  4. Bardet-Biedl syndrome. Genetics Home Reference. September 2013; http://ghr.nlm.nih.gov/condition/bardet-biedl-syndrome.
  5. Bardet-Biedl syndrome. Orphanet. 2008; http://www.orpha.net/consor/cgi-bin/Disease_Search.php?lng=EN&data_id=3244.
  6. Waters AM & Beales PL. Bardet-Biedl Syndrome. GeneReviews. April 23, 2015; http://www.ncbi.nlm.nih.gov/books/NBK1363/.
  7. Aoife M Waters, Philip L Beales. Bardet-Biedl syndrome. GeneReviews. 2015; http://www.ncbi.nlm.nih.gov/books/NBK1363/.
  8. Hufnagel RB, Amo G, Hein ND, Hersheson J, Prasad M, Anderson Y, et al.. Neuropathy target esterase impairments cause Oliver-McFarlane and Laurence-Moon syndromes. J Med Genet. February, 2015; 52(2):85-94. https://www.ncbi.nlm.nih.gov/pubmed/25480986.