Identification of the human cortactin-binding protein-2 gene from the autism candidate region at 7q31

Human chromosome 7q31 contains putative susceptibility loci for autism (AUT S1) and speech and language disorder (SPCH1). We report here the identifica tion and characterization of a novel gene encoding cortactin-binding protei n-2 (CORTBP2), which is located 45 kb telomeric to the cystic fibrosis tran smembrane conductance regulator gene (CFTR) at 7q31.3. The full-length (597 5-bp) gene was isolated and found to be composed of 23 exons encompassing 1 70 kb of DNA. In addition to being a positional candidate for AUTS1, CORTBP 2 was expressed at highest levels in the brain, as shown by northern blot a nalysis. Subsequent mutation analysis of CORTBP2 in 90 autistic patients id entified two polymorphisms, including a leucine to valine change caused by a T to G substitution in exon 15. However, comparison of allele frequencies between autistic and control populations (n = 96) showed no significant di fference, suggesting that this variant is not a susceptibility factor for a utism.