Howie P M
Behav Genet. 1981 May;11(3):227-38. doi: 10.1007/BF01065460.
It is known that concordance for stuttering is higher in monozygotic (MZ) than in dizygotic (DZ) twins. Evidence for genetic contribution to the frequency of speech disruption in stutterers was examined in 17 pairs of MZ and 13 pairs of DZ twins, each pair containing at least one stutterer. Intraclass correlations and analyses of variance indicated positive evidence for a genetic contribution to the overall frequency of disfluency in speech and to the frequency of certain types of speech disruption (blocked and prolonged sounds). There was little evidence for genetic influence on other types of speech disruption (various types of repetitions and interjections) In those disfluency types for which genetic predictions were confirmed, evidence of excessive dissimilarity in DZ cotwins suggests that a simple, additive gene-environment model is unlikely to be appropriate for disfluency frequency data.
众所周知，单卵双胞胎（MZ）中口吃的一致性高于双卵双胞胎（DZ）。在17对MZ双胞胎和13对DZ双胞胎中研究了基因对口吃者言语中断频率的影响，每对双胞胎中至少有一人口吃。组内相关系数和方差分析表明，基因对言语不流畅的总体频率以及某些类型的言语中断（阻塞音和延长音）频率有积极影响。几乎没有证据表明基因对其他类型的言语中断（各种类型的重复和插入语）有影响。在那些基因预测得到证实的不流畅类型中，DZ双胞胎过度不相似的证据表明，简单的加性基因-环境模型不太可能适用于不流畅频率数据。
