Trait

Class III obesity

Obesity with a body mass index of 40 kg per square meter or higher.

HPO HP:0025501

Also called: Obesity grade 3
Body system: Growth abnormality

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9 genes linked to Class III obesity

Changes in these genes cause rare conditions in which Class III obesity is seen. Most people with this trait have none of those conditions, and a gene on this list says nothing about anyone's own genome.

Gene	How often it is seen	Conditions
CNNM2cyclin and CBS domain divalent metal cation transport mediator 2	Often (30–79%)	In 1 condition
HERC2HECT and RLD domain containing E3 ubiquitin protein ligase 2	Often (30–79%)	In 1 condition
MAGEL2MAGE family member L2	Often (30–79%)	In 1 condition
MKRN3makorin ring finger protein 3	Often (30–79%)	In 1 condition
NPAP1nuclear pore associated protein 1	Often (30–79%)	In 1 condition
PWAR1Prader Willi/Angelman region RNA 1	Often (30–79%)	In 1 condition
PWRN1Prader-Willi region non-protein coding RNA 1	Often (30–79%)	In 1 condition
SNORD115-1small nucleolar RNA, C/D box 115-1	Often (30–79%)	In 1 condition
SNORD116-1small nucleolar RNA, C/D box 116-1	Often (30–79%)	In 1 condition

How often is among people with one of the gene's conditions, the most often across them, as the Human Phenotype Ontology records it. These pages describe traits and the research behind them; they are not a diagnosis, and a doctor or genetic counsellor is the person to ask about symptoms.

Broader traits

Obesity

Where this comes from

The Human Phenotype Ontology, release 2026-09-01: the trait, its names, its definition and the genes linked to it. Find out more at hpo.jax.org.
Data release 2026.10.16-c6eea6bf.

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