Shape and Morphology of the Sella Turcica in Patients with Trisomy 21-A Systematic Review

Background/Objectives: The sella turcica (ST) is a central craniofacial and endocrinological landmark whose morphology reflects both local skeletal development and systemic influences. Alterations in its form have been observed in various genetic syndromes, including trisomy 21 (Down syndrome, DS). Considering the characteristic craniofacial morphology of DS, this review aimed to evaluate whether individuals with DS present distinctive morphometric features and shape variants of the ST compared with non-syndromic populations and to discuss their diagnostic and clinical relevance. Methods: A systematic literature search was carried out in PubMed, the Cochrane Library, Web of Science, Wiley, MDPI, and Google Scholar on 8 May 2024. Search terms included "sella turcica," "Down syndrome," and "morphology." Studies employing lateral cephalograms, cone-beam computed tomography (CBCT), or computed tomography (CT) to assess ST morphology were included when quantitative or qualitative comparisons with control groups were available. The review followed the PRISMA 2020 guidelines and was prospectively registered in PROSPERO (CRD42024580071). Results: Only six studies fulfilled the inclusion criteria. Increased ST dimensions and a predominance of U-shaped and J-shaped variants in individuals with DS compared with controls were most frequently reported. Although the studies differed in methodology, the findings consistently indicated characteristic enlargement and remodeling of the ST in trisomy 21. Conclusions: Individuals with Down syndrome exhibit distinctive sella turcica morphology characterized by increased size and specific shape variants. The evidence base remains small and heterogeneous, with few observational studies and mixed age groups and imaging modalities, which limits the strength and generalizability of the conclusions. The present study aims to provide a modern, updated systematic review of current evidence on sella turcica morphology in patients with Down syndrome, to identify reported patterns of variation, and to explore their clinical and diagnostic significance. Recognition of these features enhances diagnostic accuracy in craniofacial evaluation, facilitates comprehensive orthodontic, endocrine, and oncological assessment, and advances understanding of cranial base development within the context of genetic syndromes.