NEPHROPATHIC CYSTINOSIS (CTNS-LSB) - CONSTRUCTION OF A YAC CONTIG COMPRISING THE REFINED CRITICAL REGION ON CHROMOSOME 17P13

A yeast artificial chromosome (YAC) contig was constructed encompassin g the entire region on chromosome 17p13 where the autosomal recessive disorder infantile nephropathic cystinosis (MIM 21980, CTNS-LSB) has b een genetically mapped, It comprises seven clones ordered by their con tent of a series of six sequence-tagged sites (STSs), Fluorescence in situ hybridisation (FISH) revealed two chimaeric clones. The order of four polymorphic STSs mapped with the contig was consistent with that of the known genetic map with the exception of markers D17S1583 (AFMb3 07zg5) and D17S1798 (AFMa202xf5) where a telomeric location of D17S158 3 was inferred from the contig; two non-polymorphic STSs were localise d within the marker framework. From the analysis of recombination even ts in an unaffected individual as defined by leucocyte cystine levels we support the high-resolution mapping of this region to a small genet ic interval and show that it is entirely represented on a single, non- chimaeric YAC clone in the contig.