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ADHD in Dutch adults: Heritability and linkage study
Author(s) -
Saviouk Viatcheslav,
Hottenga JoukeJan,
Slagboom Eline P.,
Distel Marijn A.,
de Geus Eco J.C.,
Willemsen Gonneke,
Boomsma Dorret I.
Publication year - 2011
Publication title -
american journal of medical genetics part b: neuropsychiatric genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.393
H-Index - 126
eISSN - 1552-485X
pISSN - 1552-4841
DOI - 10.1002/ajmg.b.31170
Subject(s) - heritability , linkage (software) , attention deficit hyperactivity disorder , quantitative trait locus , genetic linkage , twin study , genetics , sibling , psychology , chromosome , phenotype , biology , clinical psychology , developmental psychology , gene
Attention deficit/hyperactivity disorder (ADHD) is a neurodevelopmental phenotype that persists into adulthood. This study investigated the heritability of inattentive and hyperactive symptoms and of total ADHD symptomatology load (ADHD index) in adults and performed linkage scans for these dimensions. Data on sibling pairs and their family members from the Netherlands Twin Register with genotype and phenotype data for inattention, hyperactivity and ADHD index (∼750 sib‐pairs) were analyzed. Phenotypes were assessed with the short self‐report form of the Conners' Adult ADHD Rating Scales (CAARS). Heritabilities were estimated in SOLAR under polygenic models. Genome‐wide linkage scans were performed using variance components (VC) in MERLIN and MINX and model‐based linkage analysis was carried out in MENDEL with empirical evaluation of the results via simulations. Heritability estimates for inattention, hyperactivity and ADHD index were 35%, 23%, and 31%, respectively. Chromosomes 18q21.31–18q21.32 (VC LOD = 4.58, p emp = 0.0026) and 2p25.1 (LOD = 3.58, p emp = 0.0372) provided significant evidence for linkage for inattention and the ADHD index, respectively. The QTL on chromosome 2p25.1 also showed suggestive linkage for hyperactivity. Two additional suggestive QTLs for hyperactivity and the ADHD index shared the same location on chromosome 3p24.3–3p24.1. Finally, a suggestive QTL on 8p23.3–8p23.2 for hyperactivity was also found. Heritability of inattention, hyperactivity and total ADHD symptoms is lower in adults than in children. Chromosomes 18q and 2p are likely to harbor genes that influence several aspects of adult ADHD. © 2011 Wiley‐Liss, Inc.