GCSAML (germinal center associated signaling and motility like) is a protein-encoding gene on chromosome 1 with emerging roles in immune cell regulation and mast cell biology. The gene encodes a protein containing immunoglobulin-like domains 1, and notably carries protein-binding functionality according to GO annotations. Mechanism: GCSAML functions as a component of mast cell signaling pathways involved in type 2 immune responses. A splice-donor variant (rs56043070[A]) in GCSAML represents one of the strongest genetic associations with urticaria susceptibility (OR=1.24, P=3.6×10⁻⁴⁴), affecting mast cell-specific protein expression 2. Colocalization analysis demonstrates shared causal variants between GCSAML variants and increased GCSAML expression in skin (posterior probability=0.89) 3. Disease Relevance: GCSAML is implicated in urticaria pathogenesis through mast cell dysfunction. Genome-wide association studies identify GCSAML among genes with established roles in mast cell biology associated with urticaria susceptibility across European populations 32. The gene may participate in an IgE-independent urticaria pathway 2. Additionally, GCSAML shows elevated expression in pediatric acute myeloid leukemia samples compared to normal controls 4. Clinical Significance: GCSAML represents a potential therapeutic target for urticaria management, with genetic variants informing individualized risk stratification and the possibility of novel treatment approaches targeting mast cell activation pathways.