Rare Medical News

Disease Profile

Bardet-Biedl syndrome

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

1-9 / 1 000 000


US Estimated


Europe Estimated

Age of onset






Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

BBS; Biedl-Bardet Syndrome


Congenital and Genetic Diseases; Digestive Diseases; Endocrine Diseases;


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.


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

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.

Medical Terms Other Names
Learn More:
80%-99% of people have these symptoms
Abnormal electroretinogram
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific

[ more ]

Multicystic kidney dysplasia
Having too much body fat
Pigmentary retinopathy
Postaxial hand polydactyly
Extra little finger
Extra pinkie finger
Extra pinky finger

[ more ]

30%-79% of people have these symptoms
Decreased activity of gonads
Hypoplasia of penis
Underdeveloped penis
Hypoplasia of the ovary
Underdeveloped ovary
Involuntary, rapid, rhythmic eye movements
Short stature
Decreased body height
Small stature

[ more ]

5%-29% of people have these symptoms
Undescended testes
Undescended testis

[ more ]

Downslanted palpebral fissures
Downward slanting of the opening between the eyelids
Finger syndactyly
Generalized hirsutism
Excessive hairiness over body
Hearing impairment
Hearing defect

[ more ]

Hepatic fibrosis
Low-set, posteriorly rotated ears
Medial flaring of the eyebrow
Nephrotic syndrome
Neurological speech impairment
Speech disorder
Speech impairment
Speech impediment

[ more ]

Prominent nasal bridge
Elevated nasal bridge
High nasal bridge
Prominent bridge of nose
Prominent nasal root
Protruding bridge of nose
Protruding nasal bridge

[ more ]

Short neck
Decreased length of neck
Skeletal muscle atrophy
Muscle degeneration
Muscle wasting

[ more ]



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]


    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

        Organizations Providing General Support

          Learn more

          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

          • MedlinePlus Genetics 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.


              1. Bardet Biedl Syndrome. National Organization for Rare Disorders. 2007; https://www.rarediseases.org/rare-disease-information/rare-diseases/byID/988/viewAbstract.
              2. Forsythe E, Beales PL. Bardet-Biedl Syndrome. GeneReviews. 2015; https://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; https://ghr.nlm.nih.gov/condition/bardet-biedl-syndrome.
              5. Bardet-Biedl syndrome. Orphanet. 2008; https://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; https://www.ncbi.nlm.nih.gov/books/NBK1363/.
              7. Aoife M Waters, Philip L Beales. Bardet-Biedl syndrome. GeneReviews. 2015; https://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.

              Rare Medical News

              fascinating Rare disease knowledge right in your inbox
              Subscribe to receive