Exome sequencing to detect rare variants associated with general cognitive ability: a pilot study

Area of Science:

• Human Genetics
• Cognitive Neuroscience
• Genomics

Background:

• Individual differences in human cognitive ability are significantly heritable and impact health and social outcomes.
• Previous research focused on common genetic variants, with limited investigation into rare variants' role in cognitive ability.
• Exome sequencing has proven effective in identifying gene associations for complex traits.

Purpose of the Study:

• To investigate the impact of rare genetic variants on general cognitive ability (g) using exome sequencing.
• To compare the frequency of rare genetic variants between individuals with high cognitive ability and controls.

Main Methods:

• Exome sequencing was performed on unrelated Scottish individuals with high general cognitive ability (n=146).
• Rare genetic variant frequencies were compared to Scottish controls (n=486) with lower to middle-range cognitive scores.
• Biological pathway and global burden analyses were conducted.

Main Results:

• Pathway analysis revealed enrichment in mitochondrial inner membrane and apical cell components.
• Individuals with high cognitive ability carried a greater total number of rare variants compared to controls, contradicting a simple mutation load hypothesis.
• Non-synonymous variants showed a greater effect than synonymous variants, aligning with evolutionary hypotheses for cognitive ability.

Conclusions:

• This initial exome sequencing study of high cognitive ability suggests a role for rare genetic variants.
• The findings support further research into rare variants and their contribution to general cognitive ability in larger cohorts.
• The observed pattern of variant effects aligns with evolutionary perspectives on intelligence.