OBJECTIVES: Dysregulation of the central noradrenergic system may be involved in the pathophysiology of attention-deficit hyperactivity disorder (ADHD). The aim of this study was to examine the differences in pre- and post-treatment cerebral perfusion according to the MspI polymorphisms of the alpha-2A-adrenergic receptor gene (ADRA2A) in children with ADHD. METHODS: Thirty seven drug-naive ADHD children (8.9+1.8 years old, M=32, F=5) were genotyped. Baseline single-photon emission computed tomography (SPECT) and clinical assessments were performed for ADHD children. After treatment with methylphenidate for eight weeks, SPECT and clinical assessment were repeated. RESULTS: No differences in baseline clinical assessments or cerebral perfusion were observed according to the MspI genotype. However, after treatment, ADHD children with the G/G genotype at the MspI polymorphism showed hyperperfusion in the right cerebellar declive (p=.001, uncorrected) and hypoperfusion in the left lentiform nucleus and left cingulate gyrus (p<.001 and p=.001, uncorrected), compared to children without the G/G genotype. CONCLUSION: Although the results of this study should be interpreted cautiously, they suggest a possible role of the MspI polymorphisms of the ADRA2A gene in methylphenidate-induced changes in cerebral perfusion.
Brain ; Child ; Corpus Striatum ; Genotype ; Gyrus Cinguli ; Humans ; Methylphenidate ; Perfusion ; Pharmacogenetics ; Receptors, Adrenergic, alpha-2 ; Tomography, Emission-Computed ; Tomography, Emission-Computed, Single-Photon