Identification and genomic organization of a gene coding for a new member of the cell adhesion molecule family mapping to Xq25

The gene coding for a new member of the Immunoglobulin (Ig)-like domain-containing molecule superfamily has been identified and mapped to the human Xq25 chromosomal band. It contains 12 Ig-like domains in two clusters of 5 and 7 motifs, respectively, separated by a linker segment, followed by a transmembrane and a cytoplasmic region. The gene is conserved in mammals and is expressed in muscle, heart, brain, testis, and pancreas with transcripts of different length, suggesting that it is subjected to alternative processing. The transcript is assembled from 19 exons which are distributed along approx. 20 kb; each Ig-like domain is contained in distinct exons which constitute the unit of repeated genomic duplications. Elucidation of the IGDC1 genomic structure will allow the investigation of the basis of its alternative transcription and of its possible involvement in diseases mapped to the Xq25 interval.