dromlakhani Determine when to refer for genetic obesity syndrome testing
STEP 1 — Gather Information
Record age of obesity onset, BMI percentile or % of 95th percentile, presence of extreme hyperphagia (food seeking, waking to eat), syndromic features (developmental delay, dysmorphia, hypogonadism, etc.), family history of extreme obesity, and consanguinity.
STEP 2 — Rule In / Rule Out
If obesity onset is at or after 5 years of age, do not proceed with genetic testing for syndromic obesity; consider other etiologies such as polygenic or environmental causes.
STEP 3 — Classify or Stratify
If extreme hyperphagia or other syndromic features are present OR there is a family history of extreme obesity, proceed to referral; otherwise, do not refer for genetic testing.
STEP 4 — Decide
Order an appropriate genetic panel (e.g., leptin, leptin receptor, POMC, PCSK1, MC4R) and arrange genetic counseling for the family.
Clinical Guardrails / Mimics / Pitfalls
Do not test patients with late-onset obesity, isolated obesity without syndromic features or family history, or those with attenuated growth suggestive of endocrine causes; avoid misattributing common polygenic obesity to monogenic syndromes and remember that Prader‑Willi syndrome typically includes developmental delay and hypotonia.
Concrete Clinical Example
A 3‑year‑old presents with BMI 140% of the 95th percentile, incessant food‑seeking behavior, and a maternal cousin with severe early‑onset obesity; after confirming onset <5 years and extreme hyperphagia, the clinician orders leptin and leptin receptor testing and refers for genetic counseling.
Source: Pediatric Obesity Assessment, Treatment, and Prevention: An Endocrine Society Clinical Practice Guideline, Endocrine Society, 2017, DOI:10.1210/jc.2016-2573