The human BARX2 gene: Genomic structure, chromosomal localization, and single nucleotide polymorphisms

The BARX genes 1 and 2 are Bar class homeobox genes expressed in craniofaci al structures during development. In this report, we present the genomic st ructure, chromosomal localization, and polymorphic markers in BARX2. The ge ne has four exons, ranging in size from 85 to 1099 bp. BARX2 is localized o n human chromosome llq25, as determined by radiation hybrid mapping. In the mouse, Barx2 is coexpressed with Pitx2 in several tissues. Based on the co expression, BARX2 was assumed to be a candidate gene for those cases of Rie ger syndrome that cannot be associated with mutations of PITX2. Mutations i n PITX2 cause some cases of Rieger syndrome, an autosomal dominant disorder affecting eyes, teeth, and umbilicus. DNA from Rieger patients was subject ed to single-strand conformation polymorphism screening of the BARX2 coding region. Three single nucleotide polymorphisms were found in a normal popul ation, although no etiologic mutations were detectable in over 100 cases of Rieger syndrome or in individuals with related ocular disorders. (C)1999 A cademic Press.