FAM13A is a GTPase-activating protein (GAP) predominantly expressed in multiciliated airway epithelial cells that regulates small GTPase signaling, particularly RhoA activity 1. The FAM13A long isoform contains an N-terminal RhoGAP domain with demonstrated RhoGAP catalytic activity 1. Functionally, FAM13A coordinates cilia movement and mucociliary clearance by regulating actin cytoskeleton dynamics and epithelial cell integrity 12. Loss of FAM13A increases RhoA activity, induces F-actin stress fiber formation, and dysregulates epithelial-mesenchymal transition markers 2. Clinically, FAM13A variants represent risk alleles for multiple respiratory diseases. Genome-wide association studies identified FAM13A as a susceptibility locus for chr4 obstructive pulmonary disease (COPD) and airway obstruction independent of smoking status 34. FAM13A dysfunction may impair mucociliary clearance, increasing respiratory disease susceptibility 1. Beyond pulmonary disease, FAM13A is involved in adiposity regulation and cardiometabolic homeostasis; it was identified as a causal gene for idiopathic pulmonary fibrosis and participates in fat distribution and insulin-glucose signaling pathways 56. Genetic polymorphisms in FAM13A associate with obesity phenotypes and fat distribution in metabolically healthy women 7.