Standard terminology for phenotypic variations: the elements of morphology project, its current progress, and future directions

Abstract

In 2005, the authors of this article formed an international working group to develop standardized definitions and terms to describe the physical variations used in human phenotypic analyses. This project, which came to be known as the Elements of Morphology, resulted in six articles proposing consensus definitions for almost 400 phenotypic variations of the head and face; periorbital region; ear, nose, and philtrum; mouth and lips; and hands and feet. Every variation was accompanied by a representative figure depicting the feature. The articles were published in the January 2009 issue of the American Journal of Medical Genetics Part A and are available for free access on both the Journal's Web page and a National Institutes of Health-based site. The publication of the Elements' definitions has spawned an ongoing dialogue about the proposed terms to describe the phenotype. The working group considered the six articles as only the first step in the process, and four more articles on proposed terminology for the trunk, genital region, skin, and remainder of the limb terms are in preparation. The secondary outcome of the Elements project is the provision of a working methodology for the establishment of standardized terminology and definitions for phenotype analysis in general.