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Genetic and Rare Diseases Information Center (GARD)

Bardet-Biedl syndrome

Other Names for this Disease
  • BBS
  • Biedl-Bardet Syndrome
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What are the signs and symptoms of Bardet-Biedl syndrome?

Bardet-Biedl syndrome (BBS) affects many parts of the body, and signs and symptoms of the condition can vary among affected individuals, even in the same family. The major features include:[1][2][3]
  • Progressive vision loss due to deterioration of the retina. Typically, this begins in mid-childhood with problems with night vision and is followed by the development of blind spots in the peripheral vision. These 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 (more than 90% of the cases).
  • Extra finger next to the fifth finger (postaxial polydactyly) in about 69% of the cases.
  • Kidney problems (polycystic kidneys)  in about 53% -82% of the cases.
  • Obesity that develops around 2-3 years of age (72% of the cases).
  • Abnormalities of the genitalia and infertility (most in men) due to failure in the production of sex hormones in the body (hypogonadism) (59% of the cases) and infertility.
  • Learning disorders.
Because the signs and symptoms are highly variable and the development of some symptoms is slow, diagnosis is often made late (around 9 years old).[4081]

Bardet-Biedl syndrome may also be associated with other manifestations, including diabetes, high blood pressure, heart defects and bowel disease (Hirschsprung disease). [3][2] For this reason, it is recommended that patients are followed by a team of several specialists, such as pediatricians, cardiologists, gastroenterologists, nephrologists, ophthalmologists, etc.

Other signs and symptoms that may be present are:[1]
  • Neurological problems resulting in gait and coordination impairment
  • Speech and language problems
  • Behavioral disorders
  • Distinctive facial appearance
  • Dental abnormalities.
Last updated: 3/25/2016

The Human Phenotype Ontology provides the following list of signs and symptoms for Bardet-Biedl syndrome. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms.

Signs and Symptoms Approximate number of patients (when available)
Abnormality of the kidney 95%
Abnormal electroretinogram 90%
Abnormality of retinal pigmentation 90%
Cognitive impairment 90%
Multicystic kidney dysplasia 90%
Obesity 90%
Postaxial hand polydactyly 90%
Micropenis 88%
Myopia 75%
Astigmatism 63%
Hypertension 50%
Hypoplasia of penis 50%
Nystagmus 50%
Polycystic ovaries 50%
Short stature 50%
Cataract 30%
Glaucoma 22%
Rod-cone dystrophy 8%
Abnormality of the ovary 7.5%
Cryptorchidism 7.5%
Finger syndactyly 7.5%
Hearing impairment 7.5%
Hepatic failure 7.5%
Hypertrichosis 7.5%
Low-set, posteriorly rotated ears 7.5%
Macrocephaly 7.5%
Medial flaring of the eyebrow 7.5%
Nephrotic syndrome 7.5%
Neurological speech impairment 7.5%
Prominent nasal bridge 7.5%
Short neck 7.5%
Vaginal atresia 7.5%
Aganglionic megacolon 5%
Asthma -
Ataxia -
Autosomal recessive inheritance -
Biliary tract abnormality -
Brachydactyly syndrome -
Broad foot -
Congenital primary aphakia -
Decreased testicular size -
Delayed speech and language development -
Dental crowding -
Diabetes mellitus -
Foot polydactyly -
Gait imbalance -
Hepatic fibrosis -
High palate -
Hirsutism -
Hypodontia -
Hypogonadism -
Intellectual disability -
Left ventricular hypertrophy -
Nephrogenic diabetes insipidus -
Poor coordination -
Radial deviation of finger -
Retinal degeneration -
Short foot -
Specific learning disability -
Strabismus -
Syndactyly -

Last updated: 7/1/2016

The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature.

The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined.

Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.

  1. Bardet-Biedl syndrome. Genetics Home Reference. September 2013;
  2. Bardet-Biedl syndrome. Orphanet. 2008;
  3. Waters AM & Beales PL. Bardet-Biedl Syndrome. GeneReviews. April 23, 2015;

Other Names for this Disease
  • BBS
  • Biedl-Bardet Syndrome
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.