Genetics of attention deficit hyperactivity disorder.

Area of Science:

• Behavioral Genetics
• Psychiatric Genetics

Background:

• Attention Deficit Hyperactivity Disorder (ADHD) is a complex neurodevelopmental disorder with a significant genetic component.
• Family, twin, and adoption studies consistently demonstrate that ADHD aggregates in families, indicating a strong hereditary influence.

Purpose of the Study:

• To review the genetic underpinnings of Attention Deficit Hyperactivity Disorder (ADHD).
• To explore the role of various genetic factors, including common variants and rare mutations, in ADHD etiology and heritability.

Main Methods:

• Review of decades of genetic research on ADHD.
• Analysis of findings from family, twin, adoption, genetic linkage, genome-wide association studies (GWAS), and copy number variant (CNV) studies.

Main Results:

• ADHD exhibits high heritability, estimated at 74%.
• Genome-wide association studies (GWAS) have identified multiple genetic loci associated with ADHD.
• A significant portion of heritability is attributed to a polygenic component involving numerous common variants with small effects.
• Rare copy number variants (insertions/deletions) also contribute to ADHD heritability.

Conclusions:

• Genetic factors play a crucial role in the etiology of ADHD.
• Understanding the genetic architecture of ADHD, including polygenic and rare variant contributions, implicates novel biological pathways.
• These genetic insights hold potential for future ADHD treatment development.