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Disease Profile

Bardet-Biedl syndrome 12

Prevalence
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.

Unknown

Age of onset

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ICD-10

#N/A

Inheritance

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

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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

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X-linked
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.

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

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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.

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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.

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Not applicable

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Other names (AKA)

BBS12; Bardet-Biedl syndrome; BBS

Categories

Congenital and Genetic Diseases; Digestive Diseases; Endocrine Diseases;

Summary

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs.
orphanet

Orpha Number: 110

Definition
Bardet-Biedl syndrome (BBS) is a ciliopathy with multisystem involvement.

Epidemiology
Its prevalence in Europe is estimated at between 1/125,000 and 1/175,000.

Clinical description
This disorder is characterized by a combination of clinical signs: obesity, pigmentary retinopathy, post-axial polydactyly, polycystic kidneys, hypogenitalism, and learning disabilities, many of which appear several years after disease onset. Clinical expression is variable but most patients manifest the majority of clinical signs during the disease course. Pigmentary retinopathy is the only constant clinical sign after childhood. BBS may also be associated with several other manifestations including diabetes, hypertension, congenital cardiopathy and Hirschsprung disease (see this term).

Etiology
The wide clinical spectrum observed in BBS is associated with significant genetic heterogeneity. To date, mutations in 12 different genes (BBS1 to BBS12) have been identified as being responsible for this phenotype. These genes code for proteins involved in the development and function of primary cilia. Absence or dysfunction of BBS proteins results in ciliary anomalies in organs such as the kidney or eye. However, the relationship between symptoms and ciliary dysfunction remains obscure for some of the clinical manifestations of BBS.

Diagnostic methods
Recognition of the clinical picture is important as the diagnosis can be confirmed by molecular analysis, allowing appropriate genetic counseling for family members and possible prenatal diagnosis.

Differential diagnosis
The differential diagnosis should include the Alström, McKusick-Kaufmann and Meckel-Gruber syndromes (see these terms).

Genetic counseling
The disorder is transmitted mainly in an autosomal recessive manner but oligogenic inheritance has been reported in some cases.

Management and treatment
Patients with BBS will need multidisciplinary medical care.

Prognosis
The renal abnormalities are the main life-threatening manifestations because they can lead to end-stage renal failure and require renal transplantation. Progressive vision loss due to retinal dystrophy, together with moderate intellectual deficit (when present), behavioral anomalies, hypomimia and obesity will affect the social life of these patients.

Visit the Orphanet disease page for more resources.

Symptoms

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:
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
Aganglionic megacolon
Enlarged colon lacking nerve cells
0002251
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
Percent of people who have these symptoms is not available through HPO
Abnormality of the kidney
Abnormal kidney
0000077
Abnormality of the ovary
Abnormality of the ovaries
0000137
Allergy
0012393
Asthma
0002099
Astigmatism
Abnormal curving of the cornea or lens of the eye
0000483
Ataxia
0001251
Autosomal recessive inheritance
0000007
Biliary tract abnormality
0001080
Brachydactyly
Short fingers or toes
0001156
Broad foot
Broad feet
Wide foot

[ more ]

0001769
Cataract
Clouding of the lens of the eye
Cloudy lens

[ more ]

0000518
Decreased testicular size
Small testes
Small testis

[ more ]

0008734
Delayed speech and language development
Deficiency of speech development
Delayed language development
Delayed speech
Delayed speech acquisition
Delayed speech development
Impaired speech and language development
Impaired speech development
Language delay
Language delayed
Language development deficit
Late-onset speech development
Poor language development
Speech and language delay
Speech and language difficulties
Speech delay

[ more ]

0000750
Dental crowding
Crowded teeth
Dental overcrowding
Overcrowding of teeth

[ more ]

0000678
Diabetes mellitus
0000819
Foot polydactyly
Duplication of bones of the toes
0001829
Gait imbalance
Abnormality of balance
Abnormality of equilibrium
Imbalanced walk

[ more ]

0002141
Glaucoma
0000501
Global developmental delay
0001263
High palate
Elevated palate
Increased palatal height

[ more ]

0000218
High, narrow palate
Narrow, high-arched roof of mouth
Narrow, highly arched roof of mouth

[ more ]

0002705
Hirsutism
Excessive hairiness
0001007
Hypodontia
Failure of development of between one and six teeth
0000668
Left ventricular hypertrophy
0001712
Macrocephaly
Increased size of skull
Large head
Large head circumference

[ more ]

0000256
Micropenis
Short penis
Small penis

[ more ]

0000054
Myopia
Close sighted
Near sighted
Near sightedness
Nearsightedness

[ more ]

0000545
Nephrogenic diabetes insipidus
0009806
Poor coordination

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

  • 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) is a catalog of human genes and genetic disorders. Each entry has 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 12. Click on the link to view a sample search on this topic.

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