Autistic disorder and chromosome 15q11-q13: Construction and analysis of aBAC/PAC contig

Autistic disorder (AD) is a neurodevelopmental disorder that affects approx imately 2-10/10,000 individuals. Chromosome 15q11-q13 has been implicated i n the genetic etiology of AD based on (1) cytogenetic abnormalities; (2) in creased recombination frequency in this region in AD versus non-AD families ; (3) suggested linkage with markers D15S156, D15S219, and D15S217; and (4) evidence for significant association with polymorphisms in the gamma-amino butyric acid receptor subunit B3 gene (GABRB3), To isolate the putative 15q 11-q13 candidate AD gene, a genomic contig and physical map of the approxim ately 1.2-Mb region from the GABA receptor gene cluster to the OCA2 locus w as generated. Twenty-one bacterial artificial chromosome (BAC) clones, 32 P i-derived artificial chromosome (PAC) clones, and 2 P1 clones have been iso lated using the markers D15S540, GABRB3, GABRA5, GABRG3, D15S822, and D15S2 17, as well as 34 novel markers developed from the end sequences of BAC/ PA C clones. In contrast to previous findings, the markers D15S822 and D15S975 have been localized within the GABRG3 gene, which we have shown to be appr oximately 250 kb in size. NotI and numerous EagI restriction enzyme cut sit es were identified in this region. The BAG/PAC genomic contig can be utiliz ed for the study of genomic structure and the identification and characteri zation of genes and their methylation status in this autism candidate gene region on human chromosome 15q11-q13. (C) 1999 Academic Press.