Acquired hypothalamic obesity

When excess weight gain occurs following injury to an area of the brain called the hypothalamus.

Adolescent-onset growth hormone deficiency

A condition where the pituitary gland fails to produce enough growth hormone during adolescence.

Alström syndrome

A rare condition that affects multiple organs in the body including the kidneys, brain, heart, pancreas, liver, bladder, and bowel.

Bardet-Biedl syndrome (BBS)

A genetic syndrome that has a wide range of symptoms, including early-age childhood obesity and hard-to-control hunger.

Body mass index (BMI)

A measure that uses a person’s height and weight to work out if their weight is healthy.


Thread-like structures made up of DNA. Humans have 23 pairs of chromosomes in each cell.


A condition that causes a person's blood sugar level to become too high.


Relates to glands that secrete hormones or other products directly into the blood.


A basic unit of inheritance passed from parents to children that contains the information needed to specify physical and biological traits.

Genetic condition

A condition caused by changes in a person’s DNA sequence.

Genetic obesity

When changes in a person’s genes cause them to develop hard-to-control hunger and obesity.

Genetic testing

A medical test that looks for changes in a person’s DNA.

Genetic variant

An alteration in the most common DNA sequence.


The study of genes and the passing of genetic information and traits from parents to children.

Hard-to-control hunger/hyperphagia

An intensely increased appetite for the consumption of food.

Heart attack

A medical emergency in which the supply of blood to the heart is suddenly blocked.


Chemical messengers that are secreted directly into the blood to control the body’s functions.


Decreased functional activity of the gonads (ovaries or testes) due to sex glands producing little or no sex hormones.

Hypogonadotropic hypogonadism

A form of hypogonadism that is due to a problem with the pituitary gland or hypothalamus.


A part of the brain that maintains the body’s internal balance (homeostasis) including appetite and body weight.


When a person’s thyroid gland does not produce enough hormones.


A hormone secreted from fat cells that helps to regulate body weight.

Leptin receptor

A molecule that receives and transmits signals from leptin.

Leptin receptor (LEPR) deficiency

A rare MC4R pathway disease caused by a change in the LEPR gene meaning the leptin receptor cannot function correctly.

Melanocortin-4 receptor (MC4R) pathway

A critical pathway in the hypothalamus for the regulation of body weight.

Monogenic obesity

Obesity resulting from changes in a single gene.


A rhythmical, repetitive, and involuntary movement of the eyes.


Abnormal or excessive fat accumulation that may impair health.


Relating to deformities in bones or muscles.


Eye discomfort in bright light.


A condition in which a child is born with one or more extra fingers (or toes).

Prader-Willi syndrome

A rare genetic condition that causes a number of physical symptoms, learning difficulties and behavioural challenges.

Proopiomelanocortin (POMC) deficiency

A form of rare genetic obesity that can be caused by a change in the POMC gene.

Retinal degeneration

Deterioration of the retina caused by the progressive death of its cells.

Rod-cone dystrophy

A group of inherited eye disorders that affect the light-sensitive cells of the retina called the cones and rods.

Sensorineural hearing loss

Hearing loss caused by damage to the structures in the inner ear or auditory nerve.


A serious medical condition that happens when the blood supply to part of the brain is cut off.