The power of a statistical test is the probability that it will yield a statistically significant result given that the null hypothesis is false. In other words, it represents the chance that the study will be successful in detecting a true effect and is dependent on a number of factors, including the magnitude of the effect, the sample size and study design, and the specified false-positive ra...

Background and Purpose—A large number of candidate gene association studies have attempted to identify genes implicated in stroke, but there have been few replicable and robust associations reported. Summary of Review—The skantness of replicable associations partly relates to poor study design. Important methodological considerations include adequate sample size, the selection of appropriate co...

Background: Vitiligo is an acquired, idiopathic, and common depigmentation disorder of the skin that affects people of all ages and both sexes equally in the worldwide. Although etiology of the disease is unknown, there are theories such as environment and genetic factors. Methods: In this article, we collected and summarized the appropriate manuscripts regarding the epidemiology and gene...

In the past, to study Mendelian diseases, segregating families have been carefully ascertained for segregation analysis, followed by collecting extended multiplex families for linkage analysis. This would then be followed by association studies, using independent case-control samples and/or additional family data. Recently, for complex diseases, the initial sampling has been for a genome-wide l...