Genome-Wide Mapping of Consanguineous Families Confirms Previously Implicated Gene Loci and Suggests New Loci in Specific Language Impairment (SLI)

Specific language impairment (SLI) is a developmental disorder with substantial genetic contributions. A genome-wide linkage analysis and homozygosity mapping were performed in five consanguineous families from Pakistan. The highest LOD scores of 2.49 at 12p11.22-q11.21 in family PKSLI-31 and 1.92 at 6p in family PKSLI-20 were observed. Homozygosity mapping showed a loss of heterozygosity on 1q25.3-q32.2 and 2q36.3-q37.3 in PKSLI-20. A loss of heterozygosity mapped, in PKSLI-31 and PKSLI-34 flanks, NFXL1 and CNTNAP2, which are genes previously identified in SLI. Our findings report novel SLI loci and corroborate previously reported SLI loci, indicating the utility of a family-based approach.