FAAH2 catalyzes the hydrolysis of endogenous amidated lipids, including oleamide and anandamide, to their corresponding fatty acids, thereby regulating endocannabinoid signaling. The enzyme preferentially hydrolyzes monounsaturated substrates like anandamide compared to polyunsaturated alternatives. FAAH2 is expressed in diverse tissues including seminal vesicles, skeletal muscle, and adipose tissue, where it modulates local endocannabinoid metabolism 1. At the functional level, FAAH2 plays a role in stress response regulation; disruption of faah2a in zebrafish attenuated locomotor responses to hyperosmotic stress, suggesting the enzyme may be an important mediator of stress-associated behavior in non-rodent vertebrates 2. FAAH2 expression is differentially regulated across populations; South Asian men with overweight show 5-fold lower FAAH2 expression in skeletal muscle compared to white Caucasians 3. Genetic variants in FAAH2 have been implicated in neurodevelopmental and metabolic phenotypes. A hemizygous missense variant was identified in a male patient with anxiety disorder, autistic-like traits, intellectual disability, obesity, and hepatic steatosis 4, while another patient carrying a different FAAH2 mutation presented with autism, anxiety, ataxia, and learning disabilities 5. These findings support FAAH2 as a candidate gene for X-linked neurodevelopmental disorders with metabolic involvement, though the gene currently lacks an associated MIM phenotype.