Brunner syndrome
Encyclopedia
Brunner syndrome is a rare genetic disorder
caused by a mutation
in the MAOA gene. It is characterized by mild mental retardation
and problematic impulsive behavior (such as arson
, hypersexuality
, and aggressive posturing). It is caused by a monoamine oxidase A
(MAOA) deficiency, which leads to an excess of monoamines in the brain, such as serotonin
, dopamine
, and epinephrine
.
It was characterized in 1993.
Genetic disorder
A genetic disorder is an illness caused by abnormalities in genes or chromosomes, especially a condition that is present from before birth. Most genetic disorders are quite rare and affect one person in every several thousands or millions....
caused by a mutation
Mutation
In molecular biology and genetics, mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic...
in the MAOA gene. It is characterized by mild mental retardation
Mental retardation
Mental retardation is a generalized disorder appearing before adulthood, characterized by significantly impaired cognitive functioning and deficits in two or more adaptive behaviors...
and problematic impulsive behavior (such as arson
Arson
Arson is the crime of intentionally or maliciously setting fire to structures or wildland areas. It may be distinguished from other causes such as spontaneous combustion and natural wildfires...
, hypersexuality
Hypersexuality
Hypersexuality is extremely frequent or suddenly increased sexual urges or sexual activity. Hypersexuality is typically associated with lowered sexual inhibitions. Although hypersexuality can be caused by some medical conditions or medications, in most cases the cause is unknown...
, and aggressive posturing). It is caused by a monoamine oxidase A
Monoamine Oxidase A
Monoamine oxidase A, also known as MAO-A, is an enzyme that in humans is encoded by the MAO-A gene. Monoamine oxidase A is an isozyme of monoamine oxidase. It preferentially deaminates norepinephrine , epinephrine , serotonin, and dopamine...
(MAOA) deficiency, which leads to an excess of monoamines in the brain, such as serotonin
Serotonin
Serotonin or 5-hydroxytryptamine is a monoamine neurotransmitter. Biochemically derived from tryptophan, serotonin is primarily found in the gastrointestinal tract, platelets, and in the central nervous system of animals including humans...
, dopamine
Dopamine
Dopamine is a catecholamine neurotransmitter present in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this substituted phenethylamine functions as a neurotransmitter, activating the five known types of dopamine receptors—D1, D2, D3, D4, and D5—and their...
, and epinephrine
Epinephrine
Epinephrine is a hormone and a neurotransmitter. It increases heart rate, constricts blood vessels, dilates air passages and participates in the fight-or-flight response of the sympathetic nervous system. In chemical terms, adrenaline is one of a group of monoamines called the catecholamines...
.
It was characterized in 1993.