We used Fisher’s exact test to compare the rates of de novo mutations in the coding sequence of SYNGAP1 in samples from 94 patients with nonsyndromic mental retardation (188 chromosomes) with those of samples from 475 subjects in the other three series in the study (950 chromosomes). This comparison was performed with the use of the 2BY2 program (version 1.50 by Jurg Ott).
