Toward expression mapping of albinism-deafness syndrome (ADFN) locus on chromosome Xq26

We have employed a direct cDNA selection methodology to isolate transcribed sequences encoded in the human chromosomal interval Xq26 that contains the gene for X-chromosome linked albinism deafness syndrome (ADFN). ADFN had b een previously, mapped to an 8 centi Morgan region on chromosome Xq26. We h ave constructed six cDNA libraries specific to six YACs mapping To a 1.5 mb span at the distal boundary of the ADFN locus. The YAC specific libraries were characterized for the presence of unique cDNAs. We have identified 15 transcribed sequences from the selected cDNA libraries, These cDNAs matched to three well characterized sequences corresponding to steroid 5-alpha red uctase, ribosomal protein L28, and a short transcript that has been shown t o be expressed in human brain cortex. Seven of the cDNAs matched to express ed sequence tags or other sequences of unknown function, and Jive cDNAs sha red no homology with sequences in the public data bases. Each one of these sequences was represented as 3-10 clones in the set that was subjected to s equencing. Further characterization of these transcribed sequences may indi cate potential candidates responsible for ADFN. We have discussed the utili ty of cDNA selection methodology in assembling transcript maps and identify ing potential candidates for genetic deafness.