The authors report a series of 36 patients of Apert's Syndrome in whom a genetic analysis was performed. 2 major types of mutation were found (S252W and P253R). The correlation between the type of mutation and certain clinical abnormalities allowed validation of Upton's modification of Blauth's classification and also helped add a prognostic indicator for the intellectual development of the child. Thus, global treatment of the child should take into account not just the clinical abnormalities but also its intellectual prospects.