Abstract

Introduction

Materials & Methods

Results

Discussion & Conclusion

References

Discussion
Board

Family, twin, and adoption studies have documented a strong genetic basis for ADHD/HKD, but these studies do not identify specific genes linked to the disorder. Molecular genetic studies can identify allelic variations of specific genes that are functionally associated with ADHD/HKD, and dopamine genes have been the initial candidates based on the site of action of the stimulants drugs, which for a half century have provided the primary pharmacological treatment for ADHD/HKD. Two candidate dopamine genes have been investigated and reported to be associated with ADHD/HKD: the dopamine transporter (DAT1) gene (Cook et al, 1995 and Gill et al, 1997) and the dopamine receptor D4 (DRD4) gene (LaHoste, Swanson et al, 1996 and Swanson, Sunohara, et al, 1998; Smalley et al, 1998). Speculative hypotheses (e.g., Swanson, Castellanos et al, 1998) have suggested that specific alleles of these dopamine genes may alter dopamine transmission in the neural networks implicated in ADHD/HKD (e.g., that the 10-repeat allele of the DAT1 gene may be associated with hyperactive re-uptake of dopamine or that the 7-repeat allele of the DRD4 gene may be associated with a subsensitive postsynaptic receptor). These and other variants of the dopamine hypothesis of ADHD will be discussed.

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Presentation Number SAswanson0770
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