FLUCTUATING ASYMMETRY AND DISORDERS OF DEVELOPMENTAL ORIGIN

Environmental and/or genetic stresses may cause a breakdown in develop mental homeostasis, resulting in increased bilateral asymmetry of morp hological traits. The degree of these deviations (termed ''fluctuating asymmetry'') is thought to correlate with the severity of the stress. If these stresses also play a role in the appearance of developmental disorders, then increased morphological asymmetry may serve as a risk marker for disorders of developmental origin. This would be possible if 1) the environmental stress that caused a breakdown in developmenta l stability also contributed to the appearance of the disorder, and/or 2) the genetic predisposition (liability) to the disorder and increas ed susceptibility to fluctuating: asymmetry have a common cause. Altho ugh a number of authors have reported associations between increased f luctuating asymmetry and disorders of presumed developmental origin, t he usefulness of fluctuating asymmetry as a risk marker has not been e stablished. One obstacle to this assessment is the lack of odds ratios reported by previous authors. (C) 1996 Wiley-Liss, Inc.