Genetic latent structure analysis of dysmorphology in attention deficit disorder.

Dysmorphology--in the form of minor physical anomalies--has been frequently reported in children with attention deficit disorder (ADD). The authors report an overrepresentation of minor physical anomalies in both ADD probands and their first-degree relatives. Further, ADD probands who are not dysmorphic have non-ADD relatives who are dysmorphic; this familial pattern suggests that a single underlying factor may influence transmission of both traits. A genetic latent structure model was fit to these data to describe the factor's mode of transmission. In this analysis, an autosomal dominant model emerged. Successfully fitting this model is not equivalent to testing the validity of the model itself. Meaningful tests of the model will require larger samples than available at present, and would benefit from diagnostic refinement of the ADD and dysmorphic phenotypes.