Costello syndrome is inherited in an autosomal dominant manner, which means one copy of the altered gene is sufficient to cause the disorder. Almost all cases have resulted from new mutations, however, and occur in people with no history of the disorder in their family.
Geneticists believe that the symptoms associated with Costello syndrome are a result of a missense mutation in the HRAS gene. The HRAS gene provides instructions for making a protein that helps control cell growth and division. Mutations that cause Costello syndrome lead to the production of an HRAS protein that is permanently active. Instead of triggering cell growth in response to particular signals from outside the cell, the overactive protein directs cells to grow and divide constantly. This unchecked cell division may predispose to the development of benign and malignant tumors. It remains unclear how mutations in the HRAS gene cause the other features of Costello syndrome, but many of the signs and symptoms may result from cell overgrowth and abnormal cell division.
What are the causes of Costello syndrome?
Costello syndrome is inherited in an autosomal dominant manner, which means one copy of the altered gene is sufficient to cause the disorder. Almost all cases have resulted from new mutations, however, and occur in people with no history of the disorder in their family.
Geneticists believe that the symptoms associated with Costello syndrome are a result of a missense mutation in the {{ORGANIZATION}} gene. The {{ORGANIZATION}} gene provides instructions for making a protein that helps control cell growth and division. Mutations that cause Costello syndrome lead to the production of an HRAS protein that is permanently active. Instead of triggering cell growth in response to particular signals from outside the cell, the overactive protein directs cells to grow and divide constantly. This unchecked cell division may predispose to the development of benign and malignant tumors. It remains unclear how mutations in the {{ORGANIZATION}} gene cause the other features of Costello syndrome, but many of the signs and symptoms may result from cell overgrowth and abnormal cell division.