Viding Essi, Spinath Frank M, Price Thomas S, Bishop Dorothy V M, Dale Philip S, Plomin Robert
Social Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, London, UK.
J Child Psychol Psychiatry. 2004 Feb;45(2):315-25. doi: 10.1111/j.1469-7610.2004.00223.x.
We investigated the aetiology of language impairment in 579 four-year-old twins with low language performance and their co-twins, members of 160 MZ twin pairs, 131 same-sex DZ pairs and 102 opposite-sex DZ pairs.
Language impairment in 4-year-olds was defined by scores below the 15th percentile on a general factor derived from an extensive language test battery. Language impairment of different degrees of severity was investigated by using multiple cut-offs below the 15th percentile.
DeFries-Fulker extremes analysis indicated that language impairment as measured by the general language scale is under strong genetic influence. In addition, group differences heritability showed an increasing trend (from 38% to 76%) as a function of severity of language impairment. Although more boys are impaired than girls, incorporating opposite-sex DZ pairs into the analysis found neither quantitative nor qualitative differences between boys and girls in genetic and environmental aetiologies.
Language impairment at four years is heritable. This finding replicates previous research on language impairment and extends it by showing that language impairment is heritable in twins selected from a representative community sample. Despite the mean difference between boys and girls, genetic and environmental influences are quantitatively and qualitatively similar for language impairment for boys and girls. For both boys and girls, heritability appears to be greater for more severe language impairment, indicating stronger influence of genes at the lower end of language ability.
我们调查了579名语言能力较低的4岁双胞胎及其双胞胎同胞（160对同卵双胞胎、131对同性异卵双胞胎和102对异性异卵双胞胎）语言障碍的病因。
4岁儿童的语言障碍通过在一系列广泛的语言测试中得出的一般因素得分低于第15百分位数来定义。通过使用低于第15百分位数的多个临界值来研究不同严重程度的语言障碍。
德弗里斯-富尔克极端分析表明，一般语言量表所衡量的语言障碍受到强烈的遗传影响。此外，群体差异遗传度显示出随着语言障碍严重程度的增加而增加的趋势（从38%到76%）。虽然受影响的男孩比女孩多，但将异性异卵双胞胎纳入分析发现，男孩和女孩在遗传和环境病因方面在数量和质量上均无差异。
4岁时的语言障碍具有遗传性。这一发现重复了先前关于语言障碍的研究，并通过表明从代表性社区样本中选取的双胞胎中的语言障碍具有遗传性而对其进行了扩展。尽管男孩和女孩之间存在平均差异，但男孩和女孩在语言障碍的遗传和环境影响在数量和质量上是相似的。对于男孩和女孩来说，更严重的语言障碍的遗传度似乎更高，这表明在语言能力较低水平时基因的影响更强。
