Clinical characterisation and power simulations to detect genetic linkage in attention deficit hyperactivity disorder in antioquian families

Introduction. Attention deficit hyperactivity disorder (ADHD) is a neurobehavioural disorder whose essential characteristic is a persistent pattern of inattention or hyperactivity and impulsiveness. Recent studies into prevalence carried out on the Antioquian population by our group found an overall prevalence of 15.8%, which confirms ADHD as one of the most frequent problems in infancy. The cause of this disorder is still not altogether clear; familial aggregation of ADHD points towards a genetic component. Although to date no model of inheritance has been defined, its high prevalence rate, the difficulties involved in its diagnosis and its effects on the cognitive functions, as well as the social and educational repercussions, make this disorder a problem in children's public health. Aims. Our aim was to carry out power simulations to detect genetic linkage. Patients and methods. The Slink programme, which is part of Linkage package, was used in six families from the city of Medellin-Antioquia, which is a region where a founding effect is likely to have taken place; this makes it a strategic zone for genetic linkage studies in complex diseases such as ADHD. Results. Assuming the population to be homogenous, the lod score (Z) is greater than 3 (Z > 3) and individual lod score values of between 0 and 6 were obtained for each family. Conclusions. In this paper we discuss the benefits of having multigenerational families, in Antioquia, to conduct gene mapping studies and we examine the different strategies to be developed with the findings reported here.