Binary comparisons revealed no statistically significant differences between SHMS and DEE66 (AUC = 0.406; p = 0.692), SHMS and NOCGUS (AUC = 0.540; p = 0.366), or DEE66 and NOCGUS (AUC = 0.493; p = 0.458), suggesting potential facial overlap among these PACS1-, PACS2-, and WDR37-related syndromes and potential molecular convergence. The gene discussed is PACS1; the disease is Down syndrome.