Bardet-Biedl syndrome
 (BBS)

Understanding BBS and its association with melanocortin-4 receptor (MC4R) pathway signaling impairment.

What is BBS?

BBS is a syndromic ciliopathy, and a rare genetic disease, with an estimated US and European prevalence of 4,000 to 5,000 patients per region.3,14,19

Prevalence of BBS3,14,19

US

~4,000 to 5,000 ​ individuals

Europe

~4,000 to 5,000 ​individuals

What is the relationship between MC4R pathway impairment and BBS?

Impaired LEPR signaling reduces activation of MC4R-expressing neurons, which can cause hyperphagia and early-onset, severe obesity.2,4,5,8,10,17,21,22,24

AgRP, agouti-related peptide; BBS, Bardet-Biedl syndrome; BBSome, complex of 8 BBS proteins; LEPR, leptin receptor; MC4R, melanocortin-4 receptor; MSH, melanocyte-stimulating hormone; PCSK1, proprotein convertase subtilisin/kexin type 1; POMC, proopiomelanocortin.

AgRP, agouti-related peptide; BBS, Bardet-Biedl syndrome; BBSome, complex of 8 BBS proteins; LEPR, leptin receptor; MC4R, melanocortin-4 receptor; MSH, melanocyte-stimulating hormone; PCSK1, proprotein convertase subtilisin/kexin type 1; POMC, proopiomelanocortin.

Genes associated with BBS

At least 28 genes have been associated with BBS to date.20 BBS genes play a critical role in MC4R signaling.17,20,21 Variants in genes encoding the BBSome (a complex of 8 BBS proteins), or those that support BBSome function, can result in dysfunction of primary cilium, leading to impaired leptin receptor trafficking. This impairs MC4R pathway signaling, thereby causing hyperphagia and early-onset, severe obesity.1,5-10,12,13,15,16,18,21,23,25,26

The scientific understanding of BBS is constantly evolving; therefore, novel genes may still be discovered to be associated with BBS in the future.7,8,20

Primary Cilia Play a Role in the Development of Obesity in BBS2,4,5,9-11,18,21,24

Discover more

Learn about ways to help diagnose patients with BBS, a rare genetic disease.

BBS, Bardet-Biedl syndrome; MC4R, melanocortin-4 receptor

References

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  3. Data on file, Rhythm Pharmaceuticals.
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  14. National Organization for Rare Disorders. Accessed March 8, 2021. https://rarediseases.org/rare-diseases/bardet-biedl-syndrome/
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  20. Tomlinson JW. Bardet-Biedl syndrome: A focus on genetics, mechanisms and metabolic dysfunction. Diabetes Obes Metab. 2024; 26(Suppl. 2): 13-24. doi:10.1111/dom.15480
  21. Vaisse et al. Cold Spring Harb Perspect Biol. 2017;9:a028217.
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