Chn2, encoding chimeric protein-2, plays a pivotal role in the formation of nervous circuits by regulating axonal pruning via the Rac-GTPase system [1]. It has also been associated with various biological and disease-related processes.

Genetic studies suggest that Chn2 gene polymorphisms are related to substance dependence. In a study, the methylation levels of the Chn2 gene promoter in methamphetamine-dependent male addicts were significantly higher than those in healthy controls, indicating a significant correlation between abnormal Chn2 gene promoter methylation and methamphetamine dependence [1]. In another study, decreased expression of CHN2 was observed in neutrophil cells from adult-onset systemic lupus erythematosus (aSLE) patients, potentially providing insights into the disease mechanism [2]. A single-nucleotide polymorphism (SNP) rs39059 in CPVL/CHN2 was associated with diabetic retinopathy in Chinese type 2 diabetic patients [3]. Also, a novel polymorphism rs186911567 of the CHN2 gene was significantly associated with smoking [4].

In conclusion, Chn2 is crucial for the formation of nervous circuits. Studies related to its methylation, expression changes, and polymorphisms have provided valuable insights into its roles in substance dependence, autoimmune diseases, diabetic retinopathy, and smoking-related behaviors. These findings contribute to understanding the biological functions of Chn2 and its potential implications in various disease conditions.