It Isn’t All About the Facial Features

Abstract

Dysmorphology refers to the study of the differences in body structure resulting from abnormal development of the embryo and the fetus. The characterization of major and minor congenital anomalies has facilitated the recognition of multiple genetic and non-genetic “multiple malformation syndromes.” In the absence of a specific laboratory “biomarker” of exposure, still unidentified in spite of continuous efforts by many researchers, the physical features or stigmata of the fetal alcohol syndrome (FAS) are the most specific indication of the consequences of prenatal alcohol exposure (PAE) on growth, abnormal development of the head and face, and other external structures. However, most patients affected by PAE with a diagnostic category within the fetal alcohol spectrum disorders (FASD) do not have the growth deficits, small head circumference (HC) and the three key facial features of FAS. Even though the diagnostic criteria in most used diagnostic systems include two or three of the three classic facial features, microcephaly and growth deficits, clinical epidemiologic research has confirmed that many other facial and non-facial features are specifically associated with FAS as well, and can often be present in other patients with FASD who do not fulfil the formal criteria for FAS. In this chapter, we will review the structural defects associated with PAE that will allow recognition of FAS, including dysmorphic features and growth deficits. We will describe the full spectrum of physical anomalies associated with PAE, and not only those included in the different diagnostic schemes. We will provide a definition of the most relevant features, discuss their embryologic origin, their importance for the diagnosis of FAS and their consideration within the currently used diagnostic schemes.