Bardet-Biedl Syndrome
In a nutshell
Bardet-Biedl Syndrome (BBS) is a rare, recessively inherited disorder involving many body systems, caused by mutations in more than 20 genes involved in cilia formation and signalling. Key features include rod-cone dystrophy, obesity beginning in childhood, extra fingers or toes, kidney abnormalities and learning difficulties. The incidence is estimated at 1 in 100,000 births. There is at present no cure, but patients have access to NHS specialised multi-disciplinary clinics in London and Birmingham.
Bardet-Biedl Syndrome (BBS) is a rare, recessively inherited complex disorder that involves many body systems. Mutations in more than 20 different genes encoding proteins involved in cilia formation, maintenance and signalling can cause BBS. Genetic screening is a major part of the diagnostic pathway. There is at present no cure for Bardet-Biedl syndrome. Patients have access to NHS specialised multi-disciplinary clinics held in four centres in London and Birmingham. Bardet-Biedl Syndrome UK are third-sector partners in this service.
The incidence is estimated at 1 in 100,000 births.
Diagnosis
Beales et al (1999 and 2001) suggest that the presence of four primary features or three primary features plus two secondary features is necessary for a clinical diagnosis of Bardet-Biedl syndrome.
Primary:
- Rod-Cone Dystrophy
- Obesity which usually begins in childhood and increases in severity with age
- Extra fingers and/or toes (polydactyly) and/or partially fused digits (syndactyly)
- Kidney abnormalities, with a minority affected by renal failure
- Developmental delay, speech delay and learning difficulties
- Hypogonadism in males
Secondary:
- Speech delay/disorder
- Developmental delay
- Brachydactyly
- Polyuria/polydipsia
- Ataxia
- Poor co-ordination
- Diabetes mellitus
- Left ventricular hypertrophy
- Hepatic fibrosis
- Hypertonia
- Hearing loss
Impact of BBS
- Complex syndrome, delayed diagnosis is common
- No treatment for rod-cone dystrophy, correct early diagnosis vital for future development
- Obesity is difficult to treat, lifelong commitment to healthy diet and exercise necessary
- Learning difficulties and speech problems need early intervention for successful outcome
- Low mood, anxiety, anger and poor emotional control commonly affect adults and young people with BBS
Find out more about Bardet-Biedl Syndrome
Useful links
Last reviewed: August 2026