Latest Updates on Molecular Genetics and Pharmacogenomic Study in Child and Adolescent Psychiatric Field

Cheon, Keun Ah

Abstract

The objective of this article is to review the literature over the past decade on the molecular genetic studies and pharmacogenomic studies in child and adolescent psychiatric disorders. A computerized search was done for articles published in the past decade, and selected papers are highlighted. The past decade of research has illuminated molecular genetic studies of attention deficit hyperactivity disorder (ADHD), Tourette's disorder and autism spectrum disorder. Advances in statistical methodologies and laboratory-based gene-hunting techniques are laying the foundation for a deeper understanding of genetics that contribute to these disorders. In addition, pharmacogenomic studies of ADHD, which has mostly been done in child and adolescent psychiatric field, were reviewed in this article. ADHD is well demonstrated in clinical trials to have substantial number of patients fail to remain on therapy, and there is tremendous variability in tolerability and treatment acceptance. The majority investigated the role of candidate genes in predicting clinical response to methylphenidate. The most frequently studied is DAT1, although findings are inconsistent, with the 10-repeat polymorphism predicting both increased and decreased symptom reduction in various reports. Other candidates include DRD4, DRD5, DBH, 5HTT, SNAP-25 and COMT. Although interest in ADHD pharmacogenomics is encouraging, preliminary studies have been limited by small sample sizes, inconsistent research designs, retrospective reports and a focus on symptom response. Future studies should emphasize large, prospective trials, assess multiple medications in individual subjects and consider a full range of pharmacodynamic and pharmacokinetic outcomes.