ADHD: Genetics

0
9K


ADHD has a high heritability of 74%, meaning that 74% of the presence of ADHD in the population is due to genetic factors. There are multiple gene variants which each slightly increase the likelihood of a person having ADHD; it is polygenic and arises through the combination of many gene variants which each have a small effect. The siblings of children with ADHD are three to four times more likely to develop the disorder than siblings of children without the disorder.

Arousal is related to dopaminergic functioning, and ADHD presents with low dopaminergic functioning. Typically, a number of genes are involved, many of which directly affect dopamine neurotransmission. Those involved with dopamine include DAT, DRD4, DRD5, TAAR1, MAOA, COMT, and DBH. Other genes associated with ADHD include SERT, HTR1B, SNAP25, GRIN2A, ADRA2A, TPH2, and BDNF. A common variant of a gene called latrophilin 3 is estimated to be responsible for about 9% of cases and when this variant is present, people are particularly responsive to stimulant medication. The 7 repeat variant of dopamine receptor D4 (DRD4–7R) causes increased inhibitory effects induced by dopamine and is associated with ADHD. The DRD4 receptor is a G protein-coupled receptor that inhibits adenylyl cyclase. The DRD4–7R mutation results in a wide range of behavioural phenotypes, including ADHD symptoms reflecting split attention. The DRD4 gene is both linked to novelty seeking and ADHD. The genes GFOD1 and CDH13 show strong genetic associations with ADHD. CHD13's association with ASD, schizophrenia, bipolar disorder, and depression make it an interesting candidate causative gene. Another candidate causative gene that has been identified is ADGRL3. In zebrafish, knockout of this gene causes a loss of dopaminergic function in the ventral diencephalon and the fish display a hyperactive/impulsive phenotype.

For genetic variation to be used as a tool for diagnosis, more validating studies need to be performed. However, smaller studies have shown that genetic polymorphisms in genes related to catecholaminergic neurotransmission or the SNARE complex of the synapse can reliably predict a person's response to stimulant medication. Rare genetic variants show more relevant clinical significance as their penetrance (the chance of developing the disorder) tends to be much higher. However their usefulness as tools for diagnosis is limited as no single gene predicts ADHD. ASD shows genetic overlap with ADHD at both common and rare levels of genetic variation.

Cerca
Categorie
Leggi tutto
Business
How Do Startup CEOs Handle Decision-Making and Leadership?
In the high-stakes world of startups, where uncertainty is the norm and resources are limited,...
By Dacey Rankins 2025-05-02 15:01:19 0 4K
Business
LG launches Native Screensaver Ads. What is it?
The American company LG Ad Solutions, a division of the South Korean giant - the manufacturer of...
By Dacey Rankins 2024-09-18 17:35:52 0 15K
Telecommunications
Telecommuniations
Telecommunications is communication using electronic equipment such as telephones, computer...
By FWhoop Xelqua 2023-03-14 18:07:03 0 19K
Arts, Culture and Entertainment
Exit Through the Gift Shop (2010)
Following the style of some of the world's most prolific street artists, an amateur filmmaker...
By Leonard Pokrovski 2023-07-26 20:20:46 0 32K
Social Issues
City Lights. (1931)
With the aid of a wealthy erratic tippler, a dewy-eyed tramp who has fallen in love with a...
By Leonard Pokrovski 2022-12-11 19:38:39 0 20K
image/svg+xml


BigMoney.VIP Powered by Hosting Pokrov