Dopamine Receptor D5
The DRD5 gene provides instructions for making a protein called dopamine receptor D5, which is found in the brain. This protein works together with a chemical messenger (neurotransmitter) called dopamine. Dopamine fits into the D5 receptor like a key in a lock, which triggers chemical reactions within nerve cells. Dopamine signaling has many critical functions in the brain, including regulation of attention, mood, memory, learning, and movement.
Several studies have examined a possible relationship between a common variation (polymorphism) in the DRD5 gene and benign essential blepharospasm. The results of these studies have been mixed. Some research has suggested that the polymorphism, a short repeated segment of DNA known as allele 2, occurs more often in people with benign essential blepharospasm than in people without the disorder. However, other studies have found no connection between this polymorphism and benign essential blepharospasm. Researchers are still working to clarify whether variants in the DRD5 gene are associated with this disorder.
Other polymorphisms in the DRD5 gene appear to be associated with a common behavioral condition called attention-deficit/hyperactivity disorder (ADHD). This condition, which typically begins in childhood, is characterized by overactivity, impulsive behavior, and difficulty paying attention.
Most studies of the DRD5 gene and ADHD have focused on a polymorphism located near the beginning of the gene. The region consists of two DNA building blocks (base pairs) that are repeated multiple times in a row. The size of this segment ranges from 134 to 156 base pairs. Multiple studies have suggested that a particular variant, which is 148-base pairs long, is associated with a moderately increased risk of ADHD. However, it is unclear how this polymorphism affects the risk of the disorder.
Variations in the DRD5 gene are among many factors under study to help explain the causes of ADHD. A large number of genetic and environmental factors, most of which remain unknown, likely determine the risk of developing this complex condition.
d(1B) dopamine receptor
d(5) dopamine receptor
D1beta dopamine receptor
dopamine D5 receptor
dopamine receptor D1B