Kendler K S
Department of Psychiatry, Medical College of Virginia/Virginia Commonwealth University, Richmond.
Psychol Med. 1988 Nov;18(4):991-9. doi: 10.1017/s0033291700009910.
This paper examines the power of the sporadic v. familial method as applied to schizophrenia and major depression. The model used assumes aetiological heterogeneity with a subpopulation of cases due to a 'major' environmental event and the remainder resulting from a generalized single major locus. The findings suggest that, for sample sizes to which it is commonly applied, the sporadic v. familial classification has low power to detect aetiological heterogeneity. When applied to nuclear families, substantial power requires at a minimum 100-150 proband families. If the proportion of environmental cases in the population is low, or the 'test' for environmental aetiology in probands does not have high sensitivity and specificity, the required sample sizes are considerably larger. Adding monozygotic twins increases the power of the method, but including second-degree relatives does not. The optimal approach to the sporadic v. familial method will differ as a function of the frequency of the disorder and the relative effort and expense of examining probands versus family members. Other methods should be considered for discriminating genetic and environmental forms of illness.
本文探讨了散发性与家族性方法应用于精神分裂症和重度抑郁症时的效能。所使用的模型假定病因存在异质性，一部分病例归因于“重大”环境事件，其余病例则由一个广义的单一位点所致。研究结果表明，对于该方法通常适用的样本量而言，散发性与家族性分类在检测病因异质性方面效能较低。应用于核心家庭时，要获得足够的效能至少需要100 - 150个先证者家庭。如果人群中环境因素所致病例的比例较低，或者针对先证者环境病因的“检验”没有高灵敏度和特异性，那么所需的样本量会大得多。增加同卵双胞胎可提高该方法的效能，但纳入二级亲属则不然。散发性与家族性方法的最佳应用方式会因疾病的发病率以及检查先证者与家庭成员的相对工作量和费用而有所不同。对于区分疾病的遗传和环境形式，应考虑其他方法。
