Subchromosomal localizations for 19 X-linked expressed sequence tags (ESTs) have been determined. Two ESTs are located in Xq28, adding two novel genes to this disease-rich region. The remaining ESTs are located primarily in the pericentromeric region, with most mapping to Xp11.1-p21.1. YAC and cosmid genomic clones have been isolated for several of these loci. Available cDNAs have been used to characterize the corresponding transcripts by Northern analysis in multiple human tissues.