Association Between 5-HTTLPR Polymorphism and Tics after Treatment with Methylphenidate in Korean Children with Attention-Deficit/Hyperactivity Disorder

• Published in: Journal of child and adolescent psychopharmacology Vol. 25; no. 8; pp. 633 - 640
• Main Authors: Park, Seo Yeon, Kim, Eun Joo, Cheon, Keun-Ah
• Format: Journal Article
• Language: English
• Published: United States Mary Ann Liebert, Inc 01.10.2015
• Subjects: Adolescent; Alleles; Attention Deficit Disorder with Hyperactivity - complications; Attention Deficit Disorder with Hyperactivity - drug therapy; Attention deficit hyperactivity disorder; Behavioral sciences; Central Nervous System Stimulants - adverse effects; Central Nervous System Stimulants - therapeutic use; Child; Child & adolescent psychiatry; Dopamine; Female; Genes; Genomics; Genotype; Genotype & phenotype; Humans; Impulsivity; Male; Medical schools; Medicine; Mental disorders; Methylphenidate - adverse effects; Methylphenidate - therapeutic use; Nail Biting; Original; Polymorphism; Polymorphism, Genetic - genetics; Republic of Korea; Serotonin; Serotonin Plasma Membrane Transport Proteins - genetics; Tics - chemically induced; Tics - complications; Tics - genetics; Treatment Outcome; University colleges; Republic of Korea
• ISSN: 1044-5463; 1557-8992
• DOI: 10.1089/cap.2014.0168

The purpose of this study is to examine the relationship between 5-HTTLPR polymorphism (44-bp insertion/deletion polymorphism of serotonin transporter gene) and methylphenidate (MPH) treatment response, as well as the association between the adverse events of MPH treatment and 5-HTTLPR polymorphism in children with attention-deficit/hyperactivity disorder (ADHD). A total of 114 children with ADHD (mean age 9.08 ± 1.94 years) were recruited from the child psychiatric clinic in a hospital in South Korea. We have extracted the genomic DNA of the subjects from their blood lymphocytes and analyzed 5-HTTLPR polymorphism of the SLC6A4 gene. All children were treated with MPH for 8 weeks, with clinicians monitoring both the improvement of ADHD symptoms and the side effects. We compared the response to MPH treatment and adverse events among those with the genotype of 5-HRRLPR polymorphism. There was no significant association between the 5-HTTLPR genotype and the response to MPH treatment in children with ADHD. Subjects with the S/L+L/L genotype tended to have tics and nail biting (respectively, p < 0.001, p = 0.017). The results of this study do not support the association between the 5-HTTLPR polymorphism and treatment response with MPH in ADHD. However, our findings suggest the association between 5-HTTLPR polymorphism and the occurrence of tics and nail-biting as an adverse event of methylphenidate. This may aid in our understanding of the genetic contribution and genetic susceptibility of a particular allele in those ADHD patients with tics or nail biting.