What is Noonan Syndrome with Multiple Lentigines?
Noonan syndrome with multiple lentigines (NSML) is a genetic condition that is part of a larger group of conditions called RASopathies. RASopathies arise when something goes wrong in a pathway involved in the way the cells of our bodies communicate the information they need to function properly. Since the cells of our bodies make up our tissues, organs and organ systems, RASopathies can have widespread effects on growth, development and health. NSML has many of the same features seen in Noonan syndrome.
NSML is a very rare condition. It is estimated that it occurs in 1 in 3500 live births. Since NSML is a genetic disorder, it can be passed down from parent to child or it can be brand new (de novo) and occurs for the first time in the child affected by the condition.
What Causes NSML?
NSML occurs due to a genetic change (also called a mutation or genetic variant) in the PTPN11 and RAF1 genes. Most cases (85%) are caused by genetic changes in PTPN11. A smaller number (5 to 10%) of people with NSML have a mutation in RAF1. There are also a few known cases of NSML caused by mutations in the BRAF and MAP2K1 genes. In a very small number (1 to 5%) of cases, a specific genetic change is not identified. This is because we are still learning new information about the causes of NSML.
What Are the Signs & Symptoms of NSML?
NSML is typically diagnosed in infancy or early childhood. However, some key features of NSML may not show up until adulthood. The specific signs and symptoms of NSML vary and may appear at different ages, even within the same family. Below is a summary of the most common features seen in NSML.
How Is NSML Diagnosed?
A doctor who specializes in this disorder will complete an evaluation to confirm a diagnosis. It is diagnosed using the clinical features outlined above and then often confirmed with genetic testing. Genetic testing is done on a blood sample from the child. The purpose is to identify DNA changes in one of the genes associated with NSML.
How Is NSML Treated?
There is no single treatment for NSML. Treatment plans are created by a healthcare team with input from the patient and their family. Some symptoms may require more regular follow up with specialists than others. For example, hearing loss is usually followed closely and managed by a healthcare provider specializing in hearing and hearing loss (audiologist).
Specific recommendations for care may also depend on age. Regular follow-up exams with specialized healthcare providers can help inform appropriate screening and testing for health issues that may affect a person with NSML.
Early intervention programs are a useful support resource to help address the developmental differences often seen in children with NSML. In some cases, children with NSML may need extra support in school and benefit from an individualized education program (IEP).
What Are the Long-Term Effects of NSML?
One of the reasons it is important to confirm a diagnosis of NSML as early as possible is because the condition varies widely from person to person. As a result, the life expectancy also differs among people affected with NSML. Congenital heart defects can lead to a shortened life span.
Although some children may have more serious health complications, most children with NSML will meet most or all developmental milestones. As adults, most people with NSML function well.
Our team works closely with researchers who study RASopathies, like NSML. Thus, we are informed of cutting-edge technology and treatments that may benefit the children in our care. We can connect interested children and families with opportunities to participate in research studies that can help us better understand the RASopathies and possibly contribute to the discovery of future treatments.
To schedule a first-time or return appointment, please call the Division of Genetics directly at 312.227.6120.
For more information, please call our Clinic Coordinator, Carolyn Raski at 312.227.4391.
Noonan syndrome with multiple lentigines can bring medical challenges and significant stress in the lives of those who know and love someone with the condition. The below groups and research-based resources can help provide support for families and those affected by NSML.