A study was conducted on over 4,500 people from over 1,000 families that have at least two children diagnosed with Autism. The study included over 1,800 children diagnosed with autism and over 400 children that did not have an autism diagnosis. Seven genes (PLEKHA8, PRR25, FBXL13, VPS54, SLFN5, SNCAIP, and TGM1) that increased the risk of autism were found which were inherited from a rare DNA variation transmitted from parent to offspring. A combination of common inherited variations (polygenic risk) that increased autism likelihood were also examined. It was shown that offspring who inherited the rare mutation from unaffected parents in combination with the polygenic risk had a higher risk for having autism. The study also found that there is an effect of the genes that cause a developmental effect which delays speech. The pattern was only specific to autism and it suggests that there is a link between the genetic risk for autism and speech delay, which suggests that language delay is a core component of autism.