A novel gene isolated from human placenta located in Down syndrome critical region on chromosome 21.

Down syndrome is the most common birth defect, which is caused by trisomy 21. We identified a novel gene in the so-called Down syndrome critical region by EST mapping to genomic DNA and following cDNA cloning. The gene, designated DCRB (Down syndrome Critical Region gene B), consisted of three exons of 1095 bp in total and encoded a large open reading frame of 118 amino acid residues. The amino acids sequence of DCRB showed no significant homology to any known protein. Northern blot analysis showed that DCRB is mainly expressed in the placenta, in which a major 1.1-kb band and a minor 2.0-kb band were detected. Minor bands of 1.4 kb and 2.2 kb were also detected in adult heart and skeletal muscle.