Identification of positional candidates for neurological disorders on chromsome 13q14-->q22

In the course of a research project aimed at the molecular characterization of balanced chromosome rearrangements associated with mental retardation (MR), several YACs spanning MR-associated chromosomal rearrangements in the 13q14-->q22 region were identified. To facilitate the search for relevant candidate genes, we have analyzed a total of 102 EST clones from this region. Sequence comparisons revealed that these 102 clones represent up to 72 distinct transcripts. When no physical mapping data were available, a minimal YAC contig was screened for each unique transcript by the polymerase chain reaction (PCR) or hybridization. Fifty-eight independent ESTs could be localized to YAC clones between the markers D13S1248 and D13S1201. Several ESTs are located on YAC clones detecting chromosomal rearrangements in MR patients. One EST was mapped within the critical region for Rieger syndrome type 2, and three transcripts were identified in the region for the nocturnal enuresis type 1. Some ESTs showed homologies to known genes, including the cadherin-related tumor suppressor gene from Drosophila, the yeast mitotic control protein DIS3, and the human alpha-2-macroglobulin receptor associated protein.