A prospective study of development of children with sex chromosome anomalies - New Haven study III. The middle years.

This is the third report of a prospective study of children with sex chromosome anomalies identified at birth in New Haven, Connecticut. Previous reports in 1974 [1] and 1979 [2] summarized data from the first 2 1/2 years and the first 9 years of the children's lives, respectively. The present report will focus on progress and evaluations in the years 9-13, concluding with an Appendix of Case Summaries which provide an overview of 6 of the cases. Accumulation of data from such children is increasingly important to assist in genetic counseling. Because of the rarity of sex chromosome aneuploidy (about 1 in 400 newborns), no one center sees enough of these children to feel confident about the validity of results. However, the periodic meeting, sharing of data, and joint publication of results by investigators in several centers, made possible by the March of Dimes provide large enough numbers of children with each karyotype for valid conclusions about range of expected growth and development through the preadolescent years. Therefore, this report is published together with those from other centers, as in the 1979 report [2].