Chromosome studies in 3665 consecutive newborn children.

Results of chromosomal studies done on 3665 newborn children from central Poland have been described. As against a global incidence of 1:1022 for trisomy G and 1:1308 for the balanced translocation D/D in infants, the respective figures for the Polish infants were, 1:610 and 1:1221. Likewise, against the global incidence of 1:823 for the karyotype 47, XXY and of 1:1072 for the karyotype 47, XYY in infants, the respective incidence in the Polish infants was 1:626 and 1:939. The study has demonstrated also that the frequency of occurrence of the different widths of the C-bands had a distribution close to normal. The authors have noted that the children with chromosomal abnormalities were more frequently not as well developed at birth as were children with normal karyotypes.