Alternative titles; symbolsSPECIFIC LANGUAGE IMPAIRMENT QUANTITATIVE TRAIT LOCUS ON CHROMOSOME 13Cytogenetic location: 13q21 Genomic coordinates (GRCh38): 13...
Alternative titles; symbols
Cytogenetic location: 13q21 Genomic coordinates (GRCh38): 13:68,100,000-72,800,000
For a phenotypic description and a discussion of genetic heterogeneity of specific language impairment, see SLI1 (602081).
Children who fail to develop language normally--in the absence of explanatory factors such as neurologic disorders, hearing impairment, or lack of adequate opportunity--are clinically described as having specific language impairment.
Bartlett et al. (2002) conducted a genomewide categorical linkage analysis, using model-based lod score techniques, in 5 Canadian families of Celtic ancestry that segregated SLI. Analysis was conducted under both dominant and recessive models by use of 3 phenotypic classifications: clinical diagnosis, language impairment (spoken language quotient less than 85) and reading discrepancy (nonverbal IQ minus nonword reading greater than 15). Chromosome 13 yielded a maximum multipoint lod score of 3.92 under the recessive reading discrepancy model. Stimulation to correct for multiple models and multiple phenotypes indicated that the genomewide empirical P value was less than 0.01. As an alternative measure, they also computed the posterior probability of linkage (PPL), obtaining a PPL of 53% in the same region. Another genomic region yielded suggestive results on chromosome 2 (multipoint lod score 2.86). The findings underscored the utility of traditional lod-score-based methods in finding genes for complex diseases.
Bartlett et al. (2004) found linkage to the SLI3 region on chromosome 13q21 in a study of 22 U.S. families with at least 2 members affected with SLI. Under the recessive reading impairment model, a maximum lod score of 2.616 was obtained at D13S1317. Combining the results of the U.S. sample with the results reported by Bartlett et al. (2002) for the Canadian sample yielded a maximum lod score of 6.181 at the same marker. Haplotype analysis defined a 7-cM region on chromosome 13q21.