Laboratorio de Neuropsicología y Neurolingüística, Instituto de Neurociencias CUCBA, Universidad de Guadalajara, Guadalajara, Jalisco, Mexico.
Departamento de Farmacobiología y Departamento de Ciencias Computacionales, CUCEI, Universidad de Guadalajara, Guadalajara, Jalisco, Mexico.
Am J Med Genet B Neuropsychiatr Genet. 2018 Oct;177(7):676-684. doi: 10.1002/ajmg.b.32676. Epub 2018 Oct 19.
The objective of this study was to characterize an attention deficit hyperactivity disorder (ADHD) endophenotype in non-affected parents of adolescents with a history of ADHD, based on the relationship between performance on a sustained attention test (continuous performance task, or CPT) and polymorphisms of the DRD4 gene. In a sample of 25 non-affected parents of adolescents with ADHD history obtained from a longitudinal study of a nonclinical population, and 25 non-affected parents of adolescents with no ADHD history, four groups were evaluated with respect to the presence or absence of the long allele polymorphism of the DRD4 gene (i.e., over seven repeats). Comparisons of CPT performance among the four study groups included the number of commission errors, the number of omission errors, mean reaction time on correct responses (MRT), and reaction time (RT) variability (mean standard deviation of RT in each block [SDRT, as variability], and the sigma and tau components of the ex-Gaussian approach). The group of non-affected parents of adolescents with ADHD history and at least one long allele of the DRD4 gene showed greater RT variability (measured by SDRT), which is best explained by the greater frequency of abnormally slow responses (measured by tau). An association between the presence of the long allele of the DRD4 gene polymorphism and ADHD-like failure in CPT performance was evident in the non-affected parents of adolescents with ADHD in childhood. These findings suggest that certain traits of CPT performance could be considered an ADHD endophenotype.
本研究旨在基于持续注意力测试（连续性能任务或 CPT）表现与 DRD4 基因多态性之间的关系，对有 ADHD 病史的青少年的未受影响父母的 ADHD 内表型进行特征描述。在一项对非临床人群进行的纵向研究中，从有 ADHD 病史的青少年的 25 名未受影响父母和无 ADHD 病史的青少年的 25 名未受影响父母的样本中，根据 DRD4 基因的长等位基因多态性（即超过七个重复）的存在或不存在，对四个组进行了评估。在四个研究组中，对 CPT 表现的比较包括误报数、漏报数、正确反应的平均反应时间（MRT）和反应时间（RT）变异性（每个块中的 RT 均值标准差[SDRT，作为变异性]，以及外高斯方法的 sigma 和 tau 分量）。有 ADHD 病史的青少年的未受影响父母和至少有一个 DRD4 基因长等位基因的组显示出更大的 RT 变异性（通过 SDRT 测量），这可以通过 tau 测量的异常缓慢反应的更高频率来最好地解释。DRD4 基因多态性长等位基因的存在与儿童期 ADHD 青少年的 CPT 表现异常之间存在关联。这些发现表明，CPT 表现的某些特征可以被认为是 ADHD 的内表型。
