Langer-Giedion syndrome is a contiguous gene deletion syndrome caused by a deletion encompassing the TRPS1 and EXT1 genes. Many patients with Langer-Giedion syndrome have cytogenetically visible deletions. Most deletions in Langer-Giedion syndrome will be detected by MLPA. Only about 30% of patients with the related Type 1 Trichorhinophalangeal syndrome will have a detectable deletion by MLPA testing; most of these patients have point mutations. This laboratory performs deletion/duplication by MLPA of this region.