EXT1 and Langer-Giedion syndrome: Langer-Giedion syndrome (trichorhinophalangeal syndrome type II) is an autosomal dominant disorder caused by a deletion in chromosome 8q23.3-q24.11, which includes EXT1 and TRPS1 encoding exostosin 1 and transcriptional repressor GATA binding 1, respectively (Table 3; Lüdecke et al., 1995).