Villanueva Pia, Jara Lilian, Palomino Hernan
School of Speech and Hearing Sciences, Faculty of Medicine, University of Chile, Santiago, Chile.
Hum Biol. 2010 Aug;82(4):395-408. doi: 10.3378/027.082.0404.
Specific language impairment (SLI) is a developmental language disorder that occurs for no known reason. The disorder affects 2-8% of children. Some scientific evidence suggests that genetic factors are implicated in the etiology of SLI. The disorder is genetically complex. Two novel loci, SLI1 on chromosome 16q24 (MIM 606711) and SLI2 on chromosome 19q13 (MIM 606712), have been found to be highly correlated with SLI. Four genes have been identified as susceptibility genes. SLI occurs at an unusually elevated incidence (35%) among the population of Robinson Crusoe Island (Chile), which also has a high consanguinity rate. This finding supports the influence of genetic mechanisms in the transmission of SLI based on a founder effect. To investigate further the genetic involvement in this population, we collected blood samples from 115 islanders from 13 families with a language-impaired proband and from 18 families with a normal-language proband. The analysis of micro satellite marker D16S515, located in locus SLI1, demonstrated that the 230-bp allele was correlated with SLI and that the 232-bp allele was correlated with normal language development. The domain containing the D16S515 marker, therefore, may play a role in language development.
特定语言障碍(SLI)是一种病因不明的发育性语言障碍。该障碍影响2%至8%的儿童。一些科学证据表明,遗传因素与SLI的病因有关。该障碍具有遗传复杂性。已发现16号染色体q24上的两个新位点SLI1(MIM 606711)和19号染色体q13上的SLI2(MIM 606712)与SLI高度相关。已鉴定出四个基因作为易感基因。在鲁滨逊·克鲁索岛(智利)的人群中,SLI的发病率异常高(35%),该岛的近亲结婚率也很高。这一发现支持了基于奠基者效应的遗传机制在SLI传播中的影响。为了进一步研究该人群中的遗传因素,我们从13个有语言障碍先证者的家庭和18个有正常语言先证者的家庭中收集了115名岛民的血样。对位于SLI1位点的微卫星标记D16S515的分析表明,230-bp等位基因与SLI相关,而232-bp等位基因与正常语言发育相关。因此,包含D16S515标记的区域可能在语言发育中起作用。