Anthropometry and numerical taxonomy in clinical genetics: an example of applied biological anthropology.

Biological anthropologists can contribute a unique perspective as well as technical expertise to the diagnosis and classification of genetic disorders. Anthropometry has been used with increasing frequency to characterize syndromes and to establish ranges of variation within syndromes. The specific anthropometric-radiologic technique of metacarpophalangeal pattern profile analysis has proven useful in discriminating individuals with the Prader-Labhart-Willi (PLW) syndrome from unaffected persons. Analysis of these data also indicate a negative correlation between age and Z-score transformations of individual hand bone lengths. These findings sound a cautionary note to clinical investigators who would use the Z-score transformation to standardize for age and sex. Problems encountered in the classification of genetic syndromes afford many parallels with those faced by anthropologists in the classification of living and fossil populations. The reliance on "key" traits and the necessity of focusing on pedigree analysis results in a deemphasis of the total range of variation and typological thinking. Application of numerical taxonomic techniques to the classification of the heterogeneous connective tissue disease osteogenesis imperfecta (OI) illustrates the heuristic value of this technique and points out the need to consider phenotypic overlap when defining typologies. Clinical genetics affords just one example of an area in medicine where the unique training and generalist perspective of the biological anthropologist is in demand. The decline in the availability of positions in the traditional academic habitat for biological anthropologists makes it imperative that graduate students be aware of alternatives and that they obtain training in the practical skills which such alternatives will demand.