Historical perspective on developmental concepts and terminology

Abstract

In their ontogeny and phylogeny all living beings are historical entities. The revolution in biology of the 18th and 19th centuries that did away with the scala naturae according to which we humans, the acme of creation, “made a little lower than the angels,” also led to the gradual realization that a humble one‐celled protist (“protoctist”), such as Entamoeba histolytica of ill repute [Margulis and Chapman, ] has the same 4‐billion‐year phylogeny as that of Homo sapiens, vivid testimony to common ancestry and the relatedness of all living beings on earth. The group of medical geneticists who assembled at the NIH, Bethesda, MD this January to address terms pertaining to human ontogeny, did so in the long tradition of Sydenham, Linnaeus, Meckel, Geoffroy St‐Hilaire père et fils, Wilhelm His and so many others before who had over the previous two centuries wrestled as earnestly as they could with concepts of “classification” and nomenclature of developmental anomalies. The prior massive need for classification per se in medical morphology has diminished over the years in favor of ever more sophisticated understanding of pathogenesis and cause through experimental biology and genetics; however, in the winter of 2013 it was still found prudent to respect terminological precedent on general terms while recognizing recent advances in developmental pathology requiring clarification and definition of special terms. Efforts along similar lines instigated by the German Society of Anatomists at their first meeting in Leipzig in 1887 culminated, after intense years of work by hundreds of experts and consultants under the goad of Wilhelm His, in the Basel Nomina Anatomica [BNA, His (1895)]. His, himself, stated prefatorily that the BNA had no legislative weight, only an evanescent consensus of many to be amended in the future as needed and indicated. Without hubris, no one before or after will do the same. The more substantial the consensus the more permanent the structure. After some 120 years the BNA is alive and flourishing. Now retitled Terminologia Anatomica, it has been amended and added to many times, is still in Latin but now with synonyms in English, the new lingua franca of science, for every anatomical, histological and embryological term. May our successors be equally effective. © 2013 Wiley Periodicals, Inc.

Blastogenetic associations: General considerations

“…This definition differentiates associations from syndromes, which are causally defined [Opitz and Neri, ], even if phenotypically ascertained, for example, Down syndrome versus trisomy 21. As a result, anomalies that are part of a specific syndrome are related to a cause, and not to each other (Fig.…”

“…This particularly applies to aneuploidy. As Quan and Smith [] noted, VATER defects “may occur as part of a broader pattern of malformation in which the prognosis may vary,” and Smith, who drew attention to the importance of minor anomalies in clinical genetics [Opitz and Neri, ], omitted them from his analysis of VATER. Empirically, 79% of clinical geneticists in a recent survey felt that “dysmorphic” facial features with VACTERL would alter the diagnostic impression [Solomon et al, ].…”

“…Unfortunately, there are a number of difficulties with this statement, and even in the same issue of the journal, two consortium members still felt that associations are “real biological entities” [Opitz and Neri, ].…”

Editor's forward to special articles: Elements of morphology

“…The following two articles in this issue of the Journal by Opitz and Neri [2013] and Hennekam et al [2013] address complex issues surrounding the definitions and terminology for congenital anomalies. Opitz and Neri [2013] provide an historical foundation and Hennekam et al [2013] add the newest addition to the Elements of Morphology by proposing consensus definitions for the commonly used general terms.…”

“…Opitz and Neri [2013] provide an historical foundation and Hennekam et al [2013] add the newest addition to the Elements of Morphology by proposing consensus definitions for the commonly used general terms. Like the other papers in this series [Allanson et al, 2009] Taking up where three international working groups on malformation nomenclature left off in the 1980s, the Elements Working Group proposes standard terminology and definitions for general terms in the field, including anomaly, malformation, deformation, sequence, and syndrome.…”