Rare chromosomal deletions and duplications in attention-deficit hyperactivity disorder: a genome-wide analysis

from The Lancet

ADHD is genetic, not parenting skills or poor nutrition, it's genetic, say the 15 researchers of the latest study out of Cardiff University published in The Lancet.

Rare chromosomal deletions and duplications in attention-deficit hyperactivity disorder: a genome-wide analysis

Background

Large, rare chromosomal deletions and duplications known as copy number variants (CNVs) have been implicated in neurodevelopmental disorders similar to attention-deficit hyperactivity disorder (ADHD). We aimed to establish whether burden of CNVs was increased in ADHD, and to investigate whether identified CNVs were enriched for loci previously identified in autism and schizophrenia.

Methods

We undertook a genome-wide analysis of CNVs in 410 children with ADHD and 1156 unrelated ethnically matched controls from the 1958 British Birth Cohort. Children of white UK origin, aged 5—17 years, who met diagnostic criteria for ADHD or hyperkinetic disorder, but not schizophrenia and autism, were recruited from community child psychiatry and paediatric outpatient clinics. Single nucleotide polymorphisms (SNPs) were genotyped in the ADHD and control groups with two arrays; CNV analysis was limited to SNPs common to both arrays and included only samples with high-quality data. CNVs in the ADHD group were validated with comparative genomic hybridisation. We assessed the genome-wide burden of large (>500 kb), rare (<1% p="8·9×10−5)." p="2·0×10−6)," p="0·0077)." p="0·0008" p="0·031)." p="0·0095)" p="0·010). Interpretation Our findings provide genetic evidence of an increased rate of large CNVs in individuals with ADHD and suggest that ADHD is not purely a social construct. Funding Action Research; Baily Thomas Charitable Trust; Wellcome Trust; UK Medical Research Council; European Union.

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In the news

via Independent "Bad behaviour down to genes, not poor parenting, says study":

"Anita Thapar, professor of child and adolescent psychiatry at Cardiff University, said: "We are really excited by these findings. We have known ADHD runs in families but this is the first evidence of a direct genetic link. We hope these findings will help overcome the stigma associated with ADHD.

"Too often people dismiss it as being down to bad parenting or poor diet. As a clinician it was clear to me this was unlikely to be the case. Now we can say with confidence that ADHD is a genetic disease and that the brains of children with this condition develop differently to the brains of other children."
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For cross comparison of studies done on ADHD origin

ADHD from Pesticides-May 2010