Langer-Giedion syndrome (LGS) is a very rare genetic disorder that is characterized by distinct facial features and bone abnormalities, including thinly-growing hair, large nose and ears, and malformed fingers and toes.
LGS is caused by mutation, or damage, to genes along one section of one of the cell's chromosomes, which are the structures within each cell that control how that cell develops. The mutation that causes LGS removes a section of chromosome 8 that contains two genes, EXT1 and TRPS1.
The EXT1 gene provides the instructions for making a protein that is needed to form new blood vessels. Mutations in this gene cause a disease called hereditary multiple exostoses type 1. This disease is characterized by the growth of exostoses, which are bony growths on the ends of some bones, including those in the arms, legs, hips, and spine.
Mutations in TRPS1 cause a condition called tricho-rhino-phalangeal syndrome type 1, which is characterized by abnormal facial and head features, including sparse hair, ears that stick out, a large and round nose, and flat upper lip. People missing this gene also develop cone-shaped tips on the ends of some bones, commonly those in the hands and feet.
LGS is also called trichorhinophalangeal syndrome type II. This name refers to features that are affected by this syndrome: the hair (tricho), nose (rhino), and the fingers and toes (phalangeal).
There is currently no cure for
Langer-Giedion syndrome. Treatment helps manage the symptoms, which are not life-threatening but can adversely affect the patient's quality of life.
Autosomal dominant disorder, continuous gene deletion syndrome, exostoses, hereditary multiple exostoses type 1, Langer-Giedion syndrome, tricho-rhino-phalangeal syndrome type 1, trichorhinophalangeal syndrome, trichorhinophalangeal syndrome type II, TRPS2.