Fine mapping genetic associations between the HLA region and extremely high intelligence

Area of Science:

• Genetics
• Cognitive Neuroscience
• Immunology

Background:

• General cognitive ability (intelligence) is highly heritable and predictive of important life outcomes.
• The Human Leukocyte Antigen (HLA) region is crucial for immune function and disease but is underrepresented in genome-wide association studies (GWAS).
• A portion of intelligence heritability remains unexplained, termed 'missing heritability'.

Purpose of the Study:

• To investigate if the HLA region harbors genetic variants contributing to the missing heritability of intelligence.
• To fine-map the HLA region for genetic associations with extremely high intelligence scores.

Main Methods:

• A case-control study design was employed, including 1,393 individuals with extremely high IQ scores (>147) and 3,253 population controls.
• Imputation of genetic variants across 200 genes in the HLA region was performed.
• SNP-based heritability and polygenic score analyses were conducted.

Main Results:

• A single SNP (rs444921) met study-wide significance criteria, but SNP-based heritability for HLA variants was small and not statistically significant (0.3%).
• A polygenic score derived from HLA SNPs did not significantly predict individual intelligence differences in an independent sample.
• No significant genetic association was found between HLA variants and high intelligence.

Conclusions:

• Genetic variation within the HLA region does not appear to account for a substantial portion of the missing heritability of intelligence.
• While the HLA region is vital for many diseases, its contribution to intelligence heritability is minimal.