Linkage analysis of attention deficit hyperactivity disorder.

Area of Science:

• Genetics
• Neuroscience
• Psychiatry

Background:

• Behavioral and molecular genetic studies indicate a genetic contribution to Attention Deficit Hyperactivity Disorder (ADHD).
• Previous linkage studies for ADHD have yielded inconsistent results, lacking a clear pattern.

Purpose of the Study:

• To identify potential genes contributing to the development of ADHD.
• To investigate genetic linkage in families with ADHD using genome-wide single nucleotide polymorphism (SNP) data.

Main Methods:

• Genotyped 5,980 SNPs across the genome in 1,187 individuals from ADHD families.
• Performed affected sibling pair linkage analysis on 217 families (601 siblings).
• Conducted variance components linkage analysis using ADHD symptom count on 260 families (1,100 siblings).

Main Results:

• The affection status linkage analysis yielded a maximum LOD score of 1.85 on chromosome 8.
• The variance components linkage analysis showed a maximum LOD score of 0.8 on chromosome 8.
• No regions of significant or suggestive linkage were identified.

Conclusions:

• The findings suggest the absence of major genes with large effects influencing the ADHD phenotype.
• Further research may be needed to explore smaller genetic effects or complex gene-environment interactions in ADHD etiology.