Supplemental Material for: Phenotypic Heterogeneity in Schaaf-Yang Syndrome: Early Musculoskeletal Features and Growth Hormone Deficiency with Partial Empty Sella: A Case Report

Although neurodevelopmental and musculoskeletal features are well described, endocrine involvement remains less clearly defined.</p><p dir="ltr">Case Presentation: We report two patients with genetically confirmed SYS who demonstrated distinct clinical presentations.

The first case presented in infancy with hypotonia, developmental delay, and camptodactyly, consistent with the classical phenotype. In contrast, the second case presented in later childhood with severe growth retardation and was diagnosed with growth hormone deficiency. Pituitary magnetic resonance imaging revealed partial empty sella and pituitary hypoplasia.