The Attention-Deficit/Hyperactivity Disorder-Associated DRD4 7R Allele Predicts Household Economic Status but Not...

Area of Science:

• Human evolutionary genetics
• Behavioral genetics
• Nutritional science

Background:

• Attention-deficit/hyperactivity disorder (ADHD) affects approximately 11% of U.S. children.
• A hypothesis suggests ADHD-related behaviors may have conferred evolutionary advantages.
• The 7R allele of the dopamine receptor D4 (DRD4) gene has been linked to ADHD and showed differential effects on nutrition in nomadic versus settled adults.

Purpose of the Study:

• To investigate the association between the DRD4 7R allele and nutritional status in Rendille children.
• To explore the relationship between the DRD4 7R allele and household metrics in a related population.

Main Methods:

• Genotyping of 259 Rendille children (ages 5-10) for the DRD4 7R allele.
• Analysis of anthropometric data (height-for-age, weight-for-height Z-scores, transferrin receptor concentration) and maternal education status.
• Correlation of DRD4 7R genotype with previously collected household economic data.

Main Results:

• No significant association was found between the DRD4 7R allele and iron nutrition (TfR concentration), height-for-age (HAZ), or weight-for-height Z-scores (WHZ).
• The DRD4 7R allele was not associated with maternal education status.
• A positive association was observed between the DRD4 7R allele and household economic status (p=0.047).

Conclusions:

• The lack of association with nutritional status in children may be due to their limited role in provisioning.
• The observed association between DRD4 7R and economic success is likely influenced by parental genotypes, given their correlation with children's genotypes.
• This suggests potential evolutionary trade-offs related to the DRD4 7R allele in different environments.