This is a very rare genetic condition characterized by the bone abnormalities, distinctive facial features and malformed fingers and toes. Also known as trichorhinophalangeal syndrome II which refers to the parts of the body affected such as the hair (tricho), nose (rhino) and the digits (phalangeal). As this is a rare syndrome, the exact prevalence is not known.
Causes
This develops as the result of the deletion or the mutation in two genes on chromosome 8. The problem with the EXT1 gene causes the multiple osteochondromas and the loss of function in the TRPS1 gene causes the abnormalities of the bone and the face. If the neighboring genes are also involved, this can contribute to the varied features of this syndrome. Most cases are not the result of inheritance and develop as random events during the development of the eggs or the sperm of the parents. Only a few cases have been inherited as the chromosomal deletion from the parent with this condition. The inheritance pattern is autosomal dominant where a single copy of the defective chromosome 8 can cause the disorder.
Symptoms
The common facial features include the sparse hair, large ears, a large and a round nose, broad eyebrows and the missing indentation in the upper lip. The bone abnormalities include the bone growths that develop at the ends of bones known as exostoses and the cone-shaped ends of certain bones such as the hands and the feet. The exostoses are evident in the first few years of the child’s life and can increase in size and quantity as the children grow. This can affect the individual’s ability to bend at the joints causing pain. In some of the cases, it can also interrupt the normal bone growth resulting in short stature. Additional symptoms can include the excessive skin folds, hearing loss, delayed mental development, small head size, overly flexible joints, poor muscle tone and delayed speech.
Diagnosis
The diagnosis of Langer-Giedion Syndrome is based on the identification of the features associated with this condition. The problems become evident usually at birth presenting the distinctive facial features, sparse hair and excess skin. The X-rays can detect the ‘cone-shaped’ developments at the end of various bones and the projection of numerous tiny bones from other bones structures in the body. When the infants grow older, additional abnormalities such as mental retardation and speech delays will also become evident. The genetic testing can confirm the diagnosis by detecting the mutations of the genes that are responsible for causing this condition.
Treatment
There is no cure for Langer-Giedion Syndrome and the treatment helps with the management of the symptoms which can affect the quality of the individual’s life. The treatment is based on the symptoms that are evident in each case. Early intervention is important so the affected children can benefit from the special services such as the speech therapy, special remedial services and vocational services. The treatment can involve the surgical procedure to remove the exostoses that can result in compression of nerves and impair movements. Hearing loss may be treated with hearing aids and the physical therapy can be beneficial to improve certain movements. These children also need to be regularly monitored to identify and prevent the repeated respiratory infections. In some of the cases, the genetic counseling may be beneficial for the affected individuals and their families.
References
https://ghr.nlm.nih.gov/condition/langer-giedion-syndrome#inheritance
https://rarediseases.org/rare-diseases/trichorhinophalangeal-syndrome-type-ii/
http://www.kumc.edu/GEC/support/langer_g.html