To introduce studying publications that find variations that may predispose a person to higher (or lower) intelligence, first read this paper: "Most reported genetic associations with general intelligence are probably false positives".[PMID 23012269] This publication is also discussed in this blog
http://pss.sagepub.com/content/25/11/1975 claims to have found an explanation for ≈2% of educational attainment and cognitive function. based on rs9320913 rs11584700 rs4851266 The educational attainment page mentions a very large GWAS published in May 2016 that has found 74 regions associated with educational attainment. It is unclear whether the previous 3 SNPs are included in the newer study, though over 400,000 subjects were included and only 0.43% of the variation in educational attainment was explained by this study.
Common genetic variants underlying cognitive ability pdf book