How necessary is a chromosomal analysis in growth-retarded girls?

In growth-retarded girls, shortness may be the only clinical sign of Turner syndrome. Therefore recommendations have been published that a chromosomal analysis should be carried out in every girl showing growth retardation. The present study was carried out to examine whether the head circumference of small girls can serve as a criterion and hence limit the need for expensive chromosomal analysis. The head circumferences of 45 girls with Turner syndrome were compared with those of 41 growth-retarded girls. It could be shown that the heads of the patients with Turner syndrome had a normal circumference, whereas the heads of the control group were significantly smaller. In view of this result, the risk of overlooking Turner syndrome in diagnosing growth retardation without a chromosomal analysis could be estimated to be 1:9000. The conclusion is drawn that a chromosomal analysis is not necessary in girls whose growth retardation is combined with a small head circumference and who do not show other malformations.