ABSTRACT Apert syndrome, one of craniosynostosis syndromes caused by allelic mutations of fibroblast growth factor receptor 2 (FGFR2), is characterized by symmetrical bony syndactyly of the hands and the feet. With the mutation analysis on FGFR2 gene from eight Japanese patients with Apert syndrome, two common mutations in the seven patients, 3 cases of Ser252Trp and 4 cases of Pro253Arg were detected. In the remaining patient with an atypical phenotype of the syndrome, however, no mutations were found in the regions of the FGFR2 gene responsible for Apert syndrome and other cranio‐synostosis syndromes. In this study, the correspondence with paternal age and genotype‐phenotype correlation was not clarified. Further analysis including mass screening is necessary to discuss those correspondences in the Japanese patients associated with Apert syndrome.