PHYSICAL MAP AND COSMID CONTIG ENCOMPASSING A NEW INTERSTITIAL DELETION OF THE X-LINKED LYMPHOPROLIFERATIVE SYNDROME REGION

The X-linked lymphoproliferative syndrome (XLP) is an inherited immuno deficiency to Epstein-Barr virus infection that has been mapped to chr omosome Xq25. Molecular analysis of XLP patients from ten different fa milies identified a small interstitial constitutional deletion in 1 pa tient (XLP-D), This deletion, initially defined by a single marker, DF 83, known to map to interval Xq24-q26.1, is nested within a previously reported and much larger deletion in another XLP patient (XLP-739), A cosmid minilibrary was constructed from a single mega-YAC and used to establish a contig encompassing the whole XLP-D deletion and a portio n of the XLP-739 deletion. Based on this contig, the size of the XLP-D deletion can be estimated at 130 kb. The identification of this minim al deletion, within which at least a portion of the XLP gene is likely to reside, should greatly facilitate efforts in isolating the gene.