Polygenic risk scores for Alzheimer's disease and general cognitive function are associated with measures of cognition in older South Asians from LASI-DAD.

Genome-wide association studies (GWAS) conducted in European ancestry (EA) have identified hundreds of single nucleotide polymorphisms (SNPs) associated with general cognitive function and/or Alzheimer's disease (AD). The association between these SNPs and cognitive function has not been fully evaluated in populations with complex genetic sub-structure such as South Asians. This study investigated whether SNPs identified in EA GWASs, either individually or as polygenic risk scores (PRS), were associated with general cognitive function and five cognitive domains in 932 South Asians from the Diagnostic Assessment of Dementia for the Longitudinal Aging Study of India (LASI-DAD). We found that SNPs identified from AD GWASs were more strongly associated with cognitive function in LASI-DAD than those from a GWAS of general cognitive function. PRSs for general cognitive function and AD explained up to 1.1% of the variability in LASI-DAD cognitive domain scores. Our study represents an important stepping-stone toward better characterization of the genetic architecture of cognitive aging in the Indian/South Asian population and highlights the need for further research that may lead to the identification of new variants unique to this population.