Facial growth parameters in Down syndrome: Review of the literature and forensic application for missing persons age progression

Purpose: Individuals with Down syndrome (DS) show growth trajectories which deviate from standard ones due to variations in the growth of facial structures. Studying the effect of aging on the faces of DS individuals is necessary to obtain an accurate result through age progression, a technique based on the study of physiognomic features and used in cases of missing persons. Here we present scientific publications that delve into the rhythms of aging and morphological characteristics of facial features in DS individuals to enable appropriate age progression in cases of missing DS individuals. Results: The scientific literature considered in this review studies the growth of soft tissue and bone substrate by comparing standard growth values with those measured through anthropometric measurements of individuals with DS. Growth trajectories are described by considering morphological trends both by comparing standard values with those found in individuals with DS and by observing individual physiognomic traits. Conclusions: When a young individual with DS goes missing, the realization of an age progression requires knowledge of the aging dynamics peculiar to the DS face. Therefore, physical, cognitive, and clinical factors must be considered. Delayed physical development and early aging, such as the onset of puberty and weight gain, have an important impact on the realization of age progression. In fact, depending on the life period to be considered, the effects of aging must be calibrated based on the knowledge gathered from scientific research.