BACKGROUND: Reading disabilities (RD) and attention-deficit hyperactivity/disorder (ADHD) are two common childhood disorders that co-occur by chance more often than expected. Twin studies and overlapping genetic linkage findings indicate that shared genetic factors partially contribute to this comorbidity. Linkage of ADHD to 6p, an identified RD candidate locus, has previously been reported, suggesting the possibility of a pleiotropic gene at this locus. RD has been previously associated with five genes in the region, particularly DCDC2 and KIAA0319. METHODS: To test whether these genes also contribute to ADHD, we investigated markers previously associated with RD for association with ADHD and ADHD symptoms in a sample of families with ADHD (n = 264). Markers were located in two subregions, VMP/DCDC2 and KIAA0319/TTRAP. RESULTS: Across all analyses conducted, strong evidence for association was observed in the VMP/DCDC2 region. Association was equally strong with symptoms of both inattention and hyperactivity/impulsivity, suggesting that this locus contributes to both symptom dimensions. Markers were also tested for association with measures of reading skills (word identification, decoding); however, there was virtually no overlap in the markers associated with ADHD and those associated with reading skills in this sample. CONCLUSIONS: Overall this study supports a previous linkage study of ADHD indicating a risk gene for ADHD on 6p and points to VMP or DCDC2 as the most likely candidates.
BACKGROUND: Reading disabilities (RD) and attention-deficit hyperactivity/disorder (ADHD) are two common childhood disorders that co-occur by chance more often than expected. Twin studies and overlapping genetic linkage findings indicate that shared genetic factors partially contribute to this comorbidity. Linkage of ADHD to 6p, an identified RD candidate locus, has previously been reported, suggesting the possibility of a pleiotropic gene at this locus. RD has been previously associated with five genes in the region, particularly DCDC2 and KIAA0319. METHODS: To test whether these genes also contribute to ADHD, we investigated markers previously associated with RD for association with ADHD and ADHD symptoms in a sample of families with ADHD (n = 264). Markers were located in two subregions, VMP/DCDC2 and KIAA0319/TTRAP. RESULTS: Across all analyses conducted, strong evidence for association was observed in the VMP/DCDC2 region. Association was equally strong with symptoms of both inattention and hyperactivity/impulsivity, suggesting that this locus contributes to both symptom dimensions. Markers were also tested for association with measures of reading skills (word identification, decoding); however, there was virtually no overlap in the markers associated with ADHD and those associated with reading skills in this sample. CONCLUSIONS: Overall this study supports a previous linkage study of ADHD indicating a risk gene for ADHD on 6p and points to VMP or DCDC2 as the most likely candidates.
Authors: Timothy C Bates; Michelle Luciano; Anne Castles; Max Coltheart; Margaret J Wright; Nicholas G Martin Journal: Eur J Hum Genet Date: 2006-11-22 Impact factor: 4.246
Authors: Natalie Cope; Denise Harold; Gary Hill; Valentina Moskvina; Jim Stevenson; Peter Holmans; Michael J Owen; Michael C O'Donovan; Julie Williams Journal: Am J Hum Genet Date: 2005-02-16 Impact factor: 11.025
Authors: Erik G Willcutt; Bruce F Pennington; Richard K Olson; Nomita Chhabildas; Jacqueline Hulslander Journal: Dev Neuropsychol Date: 2005 Impact factor: 2.253
Authors: D Harold; S Paracchini; T Scerri; M Dennis; N Cope; G Hill; V Moskvina; J Walter; A J Richardson; M J Owen; J F Stein; E D Green; M C O'Donovan; J Williams; A P Monaco Journal: Mol Psychiatry Date: 2006-10-10 Impact factor: 15.992
Authors: Silvia Paracchini; Colin D Steer; Lyn-Louise Buckingham; Andrew P Morris; Susan Ring; Thomas Scerri; John Stein; Marcus E Pembrey; Jiannis Ragoussis; Jean Golding; Anthony P Monaco Journal: Am J Psychiatry Date: 2008-10-01 Impact factor: 18.112
Authors: Jillian M Couto; Izzy Livne-Bar; Katherine Huang; Zhaodong Xu; Tasha Cate-Carter; Yu Feng; Karen Wigg; Tom Humphries; Rosemary Tannock; Elizabeth N Kerr; Maureen W Lovett; Rod Bremner; Cathy L Barr Journal: Am J Med Genet B Neuropsychiatr Genet Date: 2010-03-05 Impact factor: 3.568
Authors: Matthew Ryan; Lisa A Jacobson; Cole Hague; Alison Bellows; Martha B Denckla; E Mark Mahone Journal: Child Neuropsychol Date: 2016-04-24 Impact factor: 2.500
Authors: Cecilia Marino; Paola Scifo; Pasquale A Della Rosa; Sara Mascheretti; Andrea Facoetti; Maria L Lorusso; Roberto Giorda; Monica Consonni; Andrea Falini; Massimo Molteni; Jeffrey R Gruen; Daniela Perani Journal: Cortex Date: 2014-05-09 Impact factor: 4.027
Authors: Shelley D Smith; Elena Grigorenko; Erik Willcutt; Bruce F Pennington; Richard K Olson; John C DeFries Journal: J Dev Behav Pediatr Date: 2010-09 Impact factor: 2.225
Authors: Y Wang; X Yin; G Rosen; L Gabel; S M Guadiana; M R Sarkisian; A M Galaburda; J J Loturco Journal: Neuroscience Date: 2011-06-13 Impact factor: 3.590