INTERSTITIAL DELETION OF 11 (P11.2P12) - A NEWLY DESCRIBED CONTIGUOUSGENE DELETION SYNDROME INVOLVING THE GENE FOR HEREDITARY MULTIPLE EXOSTOSES (EXT2)

Individuals with deletions of the proximal portion of the short arm of chromosome 11 share many manifestations including mental retardation, biparietal foramina, minor facial anomalies, and multiple cartilagino us exostoses. The finding of multiple exostoses in these patients is r emarkable as the disorder hereditary multiple exostoses, which is inhe rited in an autosomal dominant manner, has recently been mapped by lin kage to three regions, including proximal 11p. We report the clinical and molecular findings in an additional patient with an 11(p11.2p12) d eletion. Cytogenetic and molecular analysis demonstrated a de novo, pa ternally derived deletion for markers which have been shown to be tigh tly linked to the lip locus (EXT2). These data support the location of EXT2 within this region and also provide information regarding the or dering of polymorphic markers on 11p. Deletion 11(p11.2p12) is a rare, yet specific, deletion syndrome involving the EXT2 locus, a gene for parietal foramina, and a mental retardation locus, and therefore can b e classified as a contiguous gene deletion syndrome.