Patient Resources

Patient Resources: Genetics and the Rasopathies

How Our Bodies Work

Our bodies are made of up billions and billions of cells. Our cells read our DNA like an instruction manual to create proteins. Our cells use these proteins to communicate with each other and help our body grow and function properly. A group of proteins that interacts together is called a pathway. Miscommunication within a pathway can cause problems with a person’s development.

The Rasopathies

The rasopathies are a group of genetic conditions that are caused by genetic typos (called mutations) in a person’s DNA. Sections of our DNA make up our genes. There are numerous genes that are associated with the rasopathies. Mutations in these particular genes cause cells to have communication problems within a pathway called the RAS pathway.

The rasopathies include Noonan syndrome, Noonan syndrome with multiple lentigines, cardiofaciocutaneous syndrome, Costello syndrome, Legius syndrome, neurofibromatosis type 1, and related disorders. These conditions are separate conditions but they can have overlapping features such as skin findings, feeding problems, learning disabilities, growth problems and heart problems.

There can be a wide range of symptoms seen in individuals with a rasopathy condition. An individual may be more mildly affected or more severely affected than their family member with the same genetic mutation.

Dominant Inheritance

Sometimes a genetic mutation is inherited from a parent who also has that same condition. Other times, a child has a new mutation that was not inherited from one of his or her parents. Once someone has a rasopathy condition, there is a 50 percent chance that they will pass on that mutation to each of their children. This is called as dominant inheritance.

How Does Someone Get Diagnosed with a Rasopathy?

In some patients, a diagnosis can be made after a physical exam. In other patients, a diagnosis can be made after imaging studies such as an MRI or an echocardiogram. Genetic testing can also be helpful in establishing a diagnosis.

Genetic testing is typically performed on a blood or saliva sample. This testing is like a spellcheck for DNA that is looking for genetic typos or mutations in genes that are associated with the rasopathies.

If a genetic test comes back positive, this means that a genetic mutation has been identified in that individual. This result can be helpful because it confirms the diagnosis and we can then offer testing to other family members.

A negative test result means that we weren’t able to identify the genetic cause for the rasopathy condition. Additional genetic testing may be recommended for an individual with negative test results. This person could still have a clinical diagnosis of a rasopathy condition, even if genetic testing was negative.

To Learn More

More information about the rasopathies, support groups and research projects are available at RASopathiesNet.

Cardiofaciocutaneous Syndrome

Costello Syndrome

Neurofibromatosis Type 1

Noonan Syndrome

Noonan Syndrome with Multiple Lentigines (formerly known as LEOPARD syndrome)