Incidence of major chromosome aberrations in 12,319 newborn infants in Tokyo

Summary In order to ascertain the frequency of chromosome aberrations among newborn infants in Japan, a chromosome survey of a large number of newborn infants is in progress. A consecutive series of 12,319 newborn babies, 6382 male and 5937 female, have been screened for clinical manifestations of autosomal aberrations and for sex chromatin and sex chromosome aberrations. Chromosome studies were carried out on 694 infants with suspected chromosome aberrations. The clinically abnormal infants were screened by conventional staining, and banding techniques have been used in the part of the study performed since 1974. Of the clincally abnormal infants, 25 had abnormal karyotypes, including two males with a 47,XXY complement, one female with a 45,X complement, three male infants with a 47,XYY complement, two with trisomy 13 syndrome, three with trisomy 18 (including one case of mosaicism), eleven with Down's syndrome (including one case of mosaicism), one with B5p partial trisomy, one with cri-du-chat syndrome, and one with Y/D translocation. The overall results are comparable to those of previous population cytogenetic studies only in the autosomal trisomies and sex chromosome abnormalities and in that the observed frequencies were comparable to those found in studies in Caucasians.To whom offprint requests should be sent