Confirmation of association between attention deficit hyperactivity disorder and a dopamine transporter polymorphism

M Gill, G Daly, S Heron, Z Hawi, M Fitzgerald - Molecular psychiatry, 1997 - nature.com
M Gill, G Daly, S Heron, Z Hawi, M Fitzgerald
Molecular psychiatry, 1997nature.com
Attention deficit hyperactivity disorder (ADHD) is a common condition of childhood the
symptoms of which include inattention, excessive motor activity, inpulsivity and distractibility.
It is strongly familial 1 and twin 2 and adoption studies 3, 4 suggest that the familiality is due,
at least in part, to shared genes. Gillis et al 2 found concordance rates in ADHD for MZ and
DZ twins of 81% and 29% respectively. Stimulant drugs (eg, methylphenidate) are effective
in the treatment of ADHD 5 and inhibit the dopamine transporter. This has led to the …
Abstract
Attention deficit hyperactivity disorder (ADHD) is a common condition of childhood the symptoms of which include inattention, excessive motor activity, inpulsivity and distractibility. It is strongly familial 1 and twin 2 and adoption studies 3, 4 suggest that the familiality is due, at least in part, to shared genes. Gillis et al 2 found concordance rates in ADHD for MZ and DZ twins of 81% and 29% respectively. Stimulant drugs (eg, methylphenidate) are effective in the treatment of ADHD 5 and inhibit the dopamine transporter. This has led to the development of a hypodopaminergic hypothesis for the disease 6. Cook et al 7 examined a 3′ variable number of tandem repeat (VNTR) polymorphism at the dopamine transporter gene (DAT1) in a sample of 49 ADHD patients and their parents, using the haplotype relative risk (HRR) method. They found a significant association (χ 2= 7.29, 1 df, P= 0.007) between ADHD and the 480-bp DAT1 VNTR allele. The authors stressed the importance of independent replication and we have achieved this in a study of 40 probands and their parents, using the same robust HRR method. As in the study of Cook et al 7 we found that the 480-bp allele was preferentially transmitted to ADHD probands (χ 2= 6.07, 1 df, P= 0.014).
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