Bishop D V, North T, Donlan C
MRC Applied Psychology Unit, Cambridge, UK.
Dev Med Child Neurol. 1995 Jan;37(1):56-71. doi: 10.1111/j.1469-8749.1995.tb11932.x.
Concordance rates were compared for 63 monozygotic (MZ) and 27 dizygotic (DZ) same-sex twin pairs, aged seven years and over, selected because at least one twin met diagnostic criteria for specific speech or language impairment. There was significant heritability for developmental speech and language disorder, defined according to DSM-II-R criteria. When the definition of the phenotype was broadened to include those with a past history of disorder and those with a less pronounced discrepancy between verbal and non-verbal ability, concordance for MZ twins was close to 100 per cent, and that for DZ twins approximately 50 per cent. There was also close similarity between concordant twins for type of disorder. There is good evidence that genetic factors play a role in the aetiology of speech and language impairment; twin data may help us arrive at a clearer conception of the phenotype as well as quantifying the extent of the genetic contribution.
对63对单卵（MZ）和27对双卵（DZ）同性双胞胎进行了一致性率比较，这些双胞胎年龄在7岁及以上，入选原因是至少有一名双胞胎符合特定言语或语言障碍的诊断标准。根据《精神疾病诊断与统计手册第二版修订本》（DSM-II-R）标准定义，发育性言语和语言障碍存在显著的遗传力。当将表型的定义扩大到包括有过去障碍史的人和言语与非言语能力差异较小的人时，MZ双胞胎的一致性接近100%，DZ双胞胎的一致性约为50%。在一致的双胞胎中，障碍类型也非常相似。有充分证据表明遗传因素在言语和语言障碍的病因中起作用；双胞胎数据可能有助于我们更清楚地了解表型，并量化遗传因素的影响程度。
