Gladstien K, Spence M A
Clin Genet. 1979 Feb;15(2):171-5. doi: 10.1111/j.1399-0004.1979.tb01757.x.
Genetic heterogeneity complicates genetic counseling because the correct mode of inheritance must be determined independently for each pedigree. When autosomal and X-linked dominants inheritance mechanisms are known, as for example with retinitis pigmentosa, then only families where male-to-male transmission is observed may be readily counseled. The other pedigrees may be autosomal but lack male-to-male transmission due to chance segregation. Since only the pedigrees without male-to-male transmission are analyzed for their mode of inheritance, there is an ascertainment bias which must be corrected when evaluating the likelihood of the two inheritance patterns. A method to correct for this bias using conditional likelihoods is given, along with examples to demonstrate its use.
遗传异质性使遗传咨询变得复杂，因为每个家系都必须独立确定正确的遗传模式。当常染色体和X连锁显性遗传机制已知时，例如视网膜色素变性，那么只有观察到男性与男性之间传递的家系才能容易地进行咨询。其他家系可能是常染色体遗传，但由于随机分离而缺乏男性与男性之间的传递。由于仅对没有男性与男性之间传递的家系分析其遗传模式，所以存在一种确定偏倚，在评估两种遗传模式的可能性时必须对其进行校正。给出了一种使用条件似然性校正这种偏倚的方法，并举例说明其用法。
