Study Finds Genetic Basis of Common Diseases May Span Tens of Thousands of SNPs

Scientists in the U.S. and Korea have developed a statistical method for estimating the broad numbers of DNA variations that impact on different physical traits, such as height or childhood IQ, and on a wide range of diseases, from diabetes to bipolar disorder. Their findings, derived from analyses of existing genome-wide association studies (GWAS), suggest that any one trait or disease risk may be associated with up to tens of thousands of single nucleotide polymorphisms (SNPs) – many more than was previously thought – each of which has a minute individual effect, but which cumulatively impact significantly on trait variability or disease risk.