Learn the red flags associated with rare genetic disorders of obesity from two pediatric endocrinologists who are currently treating patients with these disorders.

Patients with rare genetic disorders of obesity rapidly gain weight early in childhood and present with a BMI greater than the 95th percentile for their age. The onset of obesity is usually between 2 to 5 years of age, although cases with an onset as early as 6 months or as late as prepubescence have been reported.

  • Heightened and prolonged hunger
  • Longer time to satiety
  • Shorter duration of satiety
  • Severe preoccupation with food
  • Food-seeking behaviors (night eating, stealing food, foraging for food in trash)
  • Distress and inappropriate response if denied food

Identifying hyperphagia

A patient and caregiver perspective.

Behaviors associated with hyperphagia

Behaviors associated with hyperphagia

Learn about the behaviors associated with insatiable hunger from the mother of a patient who is POMC heterozygous.

What hyperphagia feels like

What hyperphagia feels like

Listen to a patient with a variant of unknown significance (VOUS) explain the physical experience of hyperphagia in her own words.

The impact of hyperphagia

The impact of hyperphagia

Hear from the mother of a patient whose son is living with insatiable hunger.

Behaviors associated with hyperphagia

What hyperphagia feels like

The impact of hyperphagia

Bardet-Biedl syndrome

Estimated prevalence*: 1500-2500 (US)

Bardet-Biedl syndrome (BBS) is a genetic disorder caused by variants in one or more of the 20+ BBS genes that have been identified.1

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Alström syndrome

Estimated prevalence*: 500-1000 (worldwide)

Alström syndrome is a genetic disorder caused by variants in the ALMS1 gene.1

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POMC deficiency

Estimated prevalence*: 100-500 (US)

Proopiomelanocortin (POMC) deficiency is a disorder caused by variants in the POMC or PCSK1 genes.6

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LEPR deficiency

Estimated prevalence*: 500-2000 (US)

Leptin receptor (LEPR) deficiency is a disorder caused by variants in the LEPR gene.8

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Research into these disorders is ongoing and helps gain a better understanding of disease-causing variants. Clinical studies of investigational therapies specifically for rare genetic disorders of obesity are also underway.1,11,12

*Company-estimated number of affected individuals.


Genetic testing can play an important role in diagnosing many rare genetic disorders of obesity (e.g., MC4R deficiency, Leptin Receptor deficiency), however, some can be diagnosed by clinical features alone (e.g., Bardet-Biedl syndrome). Genetic test results should be evaluated based on clinical presentation.

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  1. Huvenne H, Duberne B, Clément K, Poitou C. Rare genetic forms of obesity: clinical approach and current treatments in 2016. Obes Facts. 2016;9(3):158-173.
  2. Kolsdorf K, Nunziata A, Funcke JB, et al. Early childhood BMI trajectories in monogenic obesity due to leptin, leptin receptor, and melanocortin 4 receptor deficiency. Int J Obes. [epub ahead of print 1 June 2017]. doi:10.1038/s41366-018-0049-6.
  3. Styne D, Arslanian S, Connor E, et al. Pediatric obesity—assessment, treatment, and prevention: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2007;102(3);709-757.
  4. McCandless SE; Committee on Genetics. Clinical report—health supervision for children with Prader-Willi syndrome. Pediatrics. 2011;127(1):195-204.
  5. Sherafat-Kazemzadeh R, Ivey L, Kahn SR, et al. Hyperphagia among patients with Bardet-Biedl syndrome. Pediatr Obes. 2013;8(5):e64-e67.
  6. Forsythe E, Beales PL Bardet-Biedl syndrome. Eur J Hum Genet. 2013;21:8-13.
  7. Marshall JD, Bronson RT, Collin GB, et al. New Alström syndrome pheontypes based on the evaluation of 182 cases. Arch Intern Med. 2005;165:675-683.
  8. Coll AP, Farooqi IS, Challis BG, Yeo GSH, O’Rahilly S. Proopiomelanocortin and energy balance: insights from human and murine genetics. J Clin Endocrinol Metab. 2004;89(6):2557-2562.
  9. Argente J, Rosenberg A, Rodeberg D, Stumpf J, Baver S, Sagal S. Clinical characteristics of human POMC, PCSK1, and LEPR deficiencies. Endocrine Abstracts. 2019;63:P976.
  10. Farooqi IS, Wangensteen T, Collins S, et al. Clinical and molecular genetic spectrum of congenital deficiency of the leptin receptor. N Engl J Med. 2007;356(3):237-247.
  11. da Fonseca ACP, Mastronardi C, Johar A, Arcos-Burgos M, Paz-Filho G. Genetics of non-syndromic childhood obesity and the use of high-throughput DNA sequencing technologies. J Diabetes Complications. 2017;31(10):1549-1561.
  12. Setmelanotide. Accessed April 1, 2020.