A TRANSCRIPTION MAP IN THE CATCH22 CRITICAL REGION - IDENTIFICATION, MAPPING, AND ORDERING OF 4 NOVEL TRANSCRIPTS EXPRESSED IN HEART

The acronym CATCH22 is used to indicate collectively a group of relate d phenotypes, namely velocardiofacial syndrome (VCFS), DiGeorge anomal y (DGA), and conotruncal anomaly face, which are associated with delet ions within 22q11.2 in the great majority of patients. A deletion map has allowed us to delimit a smallest region of deletion overlap, consi derably smaller than the commonly deleted region. We have mapped withi n this region the chromosomal breakpoint of a balanced translocation p atient presenting with a DGA/VCFS phenotype, making this region the st rongest candidate for the location of the gene(s) responsible for the disease phenotype. We report a systematic gene search in this region a nd show the presence of at least six distinct transcripts, two of whic h have been previously described. The region searched was approximatel y 270 kb; therefore, an average of one transcript every 45 kb was foun d. We generated eight new ESTs and mapped two ESTs present in public d atabases. All six transcripts are expressed in heart, an organ involve d in 70-80% of CATCH22 patients. We show that the multimethod approach to search for expressed sequences is effective and indeed necessary f or a comprehensive search and provides molecular tools for further cha racterization of the potential genes identified. (C) 1996 Academic Pre ss, Inc.