Abstract
Investigations into the genetic basis of attention-deficit/ hyperactivity disorder (ADHD) continue to yield compelling results as candidate gene studies reveal more information about this elusive disorder. Family, twin, and adoption studies further the notion that ADHD is a highly heritable disorder with direct genetic and environmental influence. The year 2005 saw many ADHD candidate gene studies, with most focused on the catecholaminergic candidates. Although many genes were studied in 2005, a large portion of findings has been supportive of the roles of dopaminergic genes’ relationship to clinical phenotypes and drug response. These studies often require replication. Clinical implications continue to be speculative, as larger sample sizes are needed to validate findings to the general population. Further understanding of endophenotypes and the impact of comorbidities also is necessary for proper clinical intervention. Forthwith, we provide a summary of ADHD genetic studies published in 2005.
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References and Recommended Reading
Faraone SV, Sergeant J, Gillberg C, Biederman J: The worldwide prevalence of ADHD: Is it an American condition? World Psychiatry 2003, 2:104–113.
Faraone SV, Perlis RH, Doyle AE, et al.: Molecular genetics of attention deficit hyperactivity disorder. Biol Psychiatry 2005, 57:1313–1323.
Faraone S, Khan S: Candidate gene studies of attention deficit activity disorder, J Clin Psychiatry 2006, In press.
Bakker SC, van der Meulen EM, Buitelaar JK, et al.: A whole-genome scan in 164 Dutch sib pairs with attention-deficit/hyperactivity disorder: suggestive evidence for linkage on chromosomes 7p and 15q. Am J Hum Genet 2003, 72:1251–1260.
Smalley SL, Kustanovich V, Minassian SL, et al.: Genetic linkage of attention-deficit/hyperactivity disorder on chromosome 16p13, in a region implicated in autism. Am J Hum Genet 2002, 71:959–963.
Fisher SE, Francks C, McCracken JT, et al.: A genomewide scan for loci involved in attention-deficit/hyperactivity disorder. Am J Hum Genet 2002, 70:1183–1196.
Arcos-Burgos M, Castellanos FX, Pineda D, et al.: Attention-deficit/hyperactivity disorder in a population isolate: linkage to loci at 4q13.2, 5q33.3, 11q22, and 17p11. Am J Hum Genet 2004, 75:998–1014.
Arnsten AF, Li BM: Neurobiology of executive functions: catecholamine influences on prefrontal cortical functions. Biol Psychiatry 2005, 57:1377–1384. This article discusses neurobiological theories of prefrontal deficits thought to be associated with executive function. It goes into much detail regarding this brain region thought to be implicated in ADHD symptoms.
Bobb AJ, Addington AM, Sidransky E, et al.: Support for association between ADHD and two candidate genes: NET1 and DRD1. Am J Med Genet B Neuropsychiatr Genet 2005, 134:67–72.
Hamarman S, Fossella J, Ulger C, et al.: Dopamine receptor 4 (DRD4) 7-repeat allele predicts methylphenidate dose response in children with attention deficit hyperactivity disorder: a pharmacogenetic study. J Child Adolesc Psychopharmacol 2004, 14:564–574. This is one of the few studies done that measured response criteria as they related to a particular allele. This study prospectively evaluated the possible relation between a treatment and a genotype.
Kirley A, Lowe N, Mullins C, et al.: Phenotype studies of the DRD4 gene polymorphisms in ADHD: association with oppositional defiant disorder and positive family history. Am J Med Genet B Neuropsychiatr Genet 2004, 131:38–42.
Lowe N, Kirley A, Mullins C, et al.: Multiple marker analysis at the promoter region of the DRD4 gene and ADHD: evidence of linkage and association with the SNP -616. Am J Med Genet B Neuropsychiatr Genet 2004, 131:33–37.
Leung PW, Lee CC, Hung SF, et al.: Dopamine receptor D4 (DRD4) gene in Han Chinese children with attention-de.-cit/hyperactivity disorder (ADHD): increased prevalence of the 2-repeat allele, Am J Med Genet B Neuropsychiatr Genet 2005, 133:54–56. This study discusses ethnic variation in ADHD. Although the phenotypic symptoms of ADHD may be similar, Chinese Han subjects reported in this article had an increased prevalence of a less common allele of DRD4.
Stein MA, Waldman ID, Sarampote CS, et al.: Dopamine transporter genotype and methylphenidate dose response in children with ADHD. Neuropsychopharmacology 2005, 30:1374–1382. This is one of the few studies that examined the 9-repeat allele of DAT and suggested a relationship with pharmacologic response. In its prospective design, the ADHD subjects with a 9-repeat DAT allele were shown to have blunted MPH response compared with those subjects without the allele.
Winsberg BG, Comings DE: Association of the dopamine transporter gene (DAT1) with poor methylphenidate response. J Am Acad Child Adolesc Psychiatry 1999, 38:1474–1477.
Cornish KM, Manly T, Savage R, et al.: Association of the dopamine transporter (DAT1) 10/10-repeat genotype with ADHD symptoms and response inhibition in a general population sample. Mol Psychiatry 2005, 10:686–698.
Hebebrand J, Dempfle A, Saar K, et al.: A genome-wide scan for attention-deficit/hyperactivity disorder in 155 German sib-pairs. Mol Psychiatry 2006, 11:196–205.
Curran S, Purcell S, Craig I, et al.: The serotonin transporter gene as a QTL for ADHD, Am J Med Genet B Neuropsychiatr Genet 2005, 134:42–47.
Li J, Wang Y, Zhou R, et al.: Serotonin 5-HT1B receptor gene and attention deficit hyperactivity disorder in Chinese Han subjects. Am J Med Genet B Neuropsychiatr Genet 2004, 132:59–63.
Domschke K, Sheehan K, Lowe N, et al.: Association analysis of the monoamine oxidase A and B genes with attention deficit hyperactivity disorder (ADHD) in an Irish sample: preferential transmission of the MAO-A 941G allele to affected children. Am J Med Genet B Neuropsychiatr Genet 2005, 134:110–114.
Loo SK, Specter E, Smolen A, et al.: Functional effects of the DAT1 polymorphism on EEG measures in ADHD. J Am Acad Child Adolesc Psychiatry 2003, 42:986–993. This study examined the neuropsychological measure of EEG and correlated it with the presence of a particular DAT polymorphism. This is important, as it touches upon a possible relationship between EEG differences in subjects possessing this polymorphism.
Doyle AE, Willcutt EG, Seidman LJ, et al.: Attention-deficit/ hyperactivity disorder endophenotypes. Biol Psychiatry 2005, 57:1324–1335. This article provides a very thorough overview and examples of endophenotypes and discusses their relevance in studies of ADHD. It also discusses the relevance of understanding endophenotypes as a component of the ADHD disease state.
Owens EB, Hinshaw SP, Kraemer HC, et al.: Which treatment for whom for ADHD? Moderators of treatment response in the MTA. J Consult Clin Psychol 2003, 71:540–552.
Roman T, Schmitz M, Polanczyk GV, et al.: Is the alpha-2A adrenergic receptor gene (ADRA2A) associated with attention-deficit/hyperactivity disorder? Am J Med Genet B Neuropsychiatr Genet 2003, 120:116–120.
Volk HE, Neuman RJ, Todd RD: A systematic evaluation of ADHD and comorbid psychopathology in a population-based twin sample. J Am Acad Child Adolesc Psychiatry 2005, 44:768–775.
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Khan, S.A., Faraone, S.V. The genetics of ADHD: A literature review of 2005. Curr Psychiatry Rep 8, 393–397 (2006). https://doi.org/10.1007/s11920-006-0042-y
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DOI: https://doi.org/10.1007/s11920-006-0042-y