Langer-Giedion syndrome is a condition that causes bone abnormalities and distinctive facial features. People with this condition have multiple noncancerous (benign) bone tumors called osteochondromas. Multiple osteochondromas may result in pain, limited range of joint movement, and pressure on nerves, blood vessels, the spinal cord, and tissues surrounding the osteochondromas. Affected individuals also have short stature and cone-shaped ends of the long bones (epiphyses). The characteristic appearance of individuals with Langer-Giedion syndrome includes sparse scalp hair, a rounded nose, a long flat area between the nose and the upper lip (philtrum), and a thin upper lip. Some people with this condition have loose skin in childhood, which typically resolves with age. Affected individuals may have some intellectual disability.
Langer-Giedion syndrome is a rare condition; its incidence is unknown.
Langer-Giedion syndrome is caused by the deletion or mutation of at least two genes on chromosome 8. Researchers have determined that the loss of a functional EXT1 gene is responsible for the multiple osteochondromas seen in people with Langer-Giedion syndrome. Loss of a functional TRPS1 gene may cause the other bone and facial abnormalities. The EXT1 gene and the TRPS1 gene are always missing or mutated in affected individuals, but other neighboring genes may also be involved. The loss of additional genes from this region of chromosome 8 likely contributes to the varied features of this condition.
Langer-Giedion syndrome is often described as a contiguous gene deletion syndrome because it results from the loss of several neighboring genes.
Most cases of Langer-Giedion syndrome are not inherited, but occur as random events during the formation of reproductive cells (eggs or sperm) in a parent of an affected individual. These cases occur in people with no history of the disorder in their family. There have been very few instances in which people with Langer-Giedion syndrome have inherited the chromosomal deletion from a parent with the condition.
- Giedion-Langer Syndrome
- tricho-rhino-phalangeal syndrome type II
- trichorhinophalangeal syndrome type II
- TRPS II