Find a healthcare providerGlossary
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Autosomal Recessive
Autosomal recessive (AR) conditions occur when a person inherits two non-working copies of a disease-causing (pathogenic) gene variant from their parents.
Adrenocorticotropic Hormone (ACTH)
ACTH is a hormone produced by the small adrenal glands located on the top of the kidneys. Reduced ACTH levels cause a condition called adrenal insufficiency. In individuals with POMC deficiency, adrenal insufficiency often results in extended periods of extremely low blood sugar (hypoglycemia).
Acanthosis Nigricans
A skin condition characterized by patches of darkened (light brown to black), thickened, velvety skin in the body’s folds and creases. These patches may be found in the neck, armpits, groin, or other places on the body.
Adolescent-Onset Growth Hormone Deficiency
Growth hormone deficiency is a condition where the body does not have enough of the hormone that helps us grow. Many factors, including genetics, can cause this condition. When it begins in adolescence, it is known as adolescent-onset growth hormone deficiency.
Astigmatism
A common condition where the front surface of the eye has an irregular curve, causing blurred vision.
Benign Variant
A variant or change in a gene that is not going to cause health problems. This is considered a “negative” result.
Brachydactyly
A shortening of the fingers and toes due to unusually short bones.
Cardiomyopathy
A condition where the heart is abnormally enlarged, which compromises its ability to pump blood to the rest of the body.
Carrier
In an autosomal recessive inheritance pattern, if an individual inherits one normal copy of a gene and one copy of a disease-causing variant, they are called a carrier and will generally not have any symptoms of the disease that variant causes.
Cataracts
A condition in which the lens of the eye becomes progressively cloudy, resulting in blurred vision.
Cone-Rod Dystrophy
An eye condition that causes light-sensing cells called cones and rods in the retina (the back part of the eye) to deteriorate, leading to progressive vision loss. In people with cone-rod dystrophy, cones typically break down before the rods, causing sensitivity to light and impaired color vision to be the first type of vision loss. When the rods begin deteriorating, night vision is disrupted. This condition is similar to rod-cone dystrophy but differs in the order of vision loss.
Endocrine Abnormalities
The endocrine system is made of organs, glands, and hormones that tell the body how to do its job. This system influences how your heart beats, how you use the food you eat, how you grow, and many other important body functions. An endocrine abnormality means that one or more parts of the system is not working the way it should.
Energy-Balance System/Energy Expenditure
How the body balances the calories we consume and the calories we expend. An imbalance in this system can lead to weight changes.
Gene
Our body’s instruction manual that informs how our bodies grow, develop, and function. It is through our genes that traits are passed down from parent to offspring.
Genetic Counselor
A healthcare provider with in-depth training in genetic science and counseling who helps people understand complicated genetic topics and adapt to the medical, emotional, and familial implications of genetic diseases.
Genetic Variant
Changes (also known as variants) in the standard “spelling” of a gene. Gene variants can result in serious health problems or be “silent” with no negative health effects.
Heterozygote
An individual with one normal copy of a gene and one copy with a genetic variant.
Homozygote
An individual with two copies of a gene with a genetic variant.
Hormone
Chemical messengers made in the endocrine glands that control body functions.
Hyperphagia
Insatiable hunger, which is a deep hunger that doesn’t go away—it can feel like your hunger is stuck in the “on” position, even after eating. Common experiences include intense hunger that doesn’t go away, taking a longer time to feel full while eating, feeling hungry again right after a meal, thinking about food constantly, constantly looking for food (night eating, stealing food, eating discarded food), and becoming very upset when food is unavailable.
Hypogonadotropic Hypogonadism (HH)
A rare disorder of delayed puberty that happens when levels of gonadotropin hormones (Gn) are too low, which leads to low levels of other key hormones like follicle-stimulating hormone (FSH) and luteinizing hormone (LH).
Hypothalamus
A small part of the brain that has an important role in controlling many bodily functions, including the release of hormones from the pituitary gland. This is where the MC4R pathway is located.
Hypothyroidism
A condition caused when the thyroid doesn’t make enough of certain hormones. Symptoms of hypothyroidism include fatigue, constipation, poor temperature regulation, and thinning hair.
Leptin Receptor
An important receptor that helps the body regulate weight. The hormone leptin docks or attaches to the leptin receptor, much like a docking station.
Likely Benign Variant
A variant in a gene that is probably not going to cause health problems. This is considered a probably “negative” result.
Likely Pathogenic Variant
A variant in a gene that is expected or likely to cause health issues.
Manifesting Heterozygote
When a “carrier” who has only one copy of a gene with a variant has the signs and symptoms of a genetic condition that ordinarily requires two copies with variants.
Melanocortin-4 Receptor (MC4R) Pathway
The MC4R pathway is one of the pathways that regulates weight and appetite in the brain. Click here to learn more about the MC4R pathway.
Medical Geneticist
A specialist doctor with additional in-depth training in genetics and medicine.
Metabolic Rate
The rate at which the body uses energy.
Nystagmus
Uncontrolled movements of the eye.
Pathogenic Variant
A variant in a gene that is expected to cause health issues.
Photophobia
Increased sensitivity to light.
Polydactyly
The presence of extra toes and/or fingers.
Polydipsia
Abnormally great thirst as a symptom of disease (such as diabetes) or psychological disturbance.
Polyuria
A condition where the body urinates more than usual and passes excessive or abnormally large amounts of urine each time you urinate.
Rod-Cone Dystrophy
An eye condition that causes light-sensing cells called cones and rods in the retina (the back part of the eye) to deteriorate, leading to a progressive vision loss. In people with rod-cone dystrophy, rods typically break down before cones, causing night vision to be the first type of vision lost. When the cones begin to deteriorate, daylight and color vision are affected. Retinitis Pigmentosa is one of the most common forms of rod-cone dystrophy. This condition is similar to cone-rod dystrophy but differs in the order of type of vision lost.
Satiety
The feeling of fullness after a meal.
Signals
Chemicals and proteins that the body and brain use to communicate and direct processes in the body.
Strabismus
A condition in which the eyes don’t look in exactly the same direction at the same time. This is also known as “crossed eyes” or eye misalignment.
Syndactyly
A condition wherein two or more digits are fused together.
Uniparental Disomy
A genetic difference in which two copies of a gene or chromosome come from the same parent, instead of one copy coming from each parent.
Variants
Genetic variants may result in serious health problems or be “silent” with no negative health effects.
Variant of Uncertain Significance (VUS or VOUS)
A variant in a gene that may or may not cause health issues, but there is not enough information available to know for sure. This variant may be recategorized as “benign” or “disease-causing” as more information becomes available.
