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Genetic and Rare Diseases Information Center (GARD)

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Milroy disease

Other Names for this Disease
  • Congenital hereditary lymphedema
  • Early onset lymphedema
  • Hereditary lymphedema
  • Hereditary lymphedema 1
  • Milroy's disease
More Names
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Your Question

I have two older brothers with Milroy disease. I do not exhibit any signs or symptoms of the condition. I am currently pregnant and was under the impression that since I do not show the signs of Milroy disease that my offspring would not be at risk for this disorder. Am I correct in my understanding that an autosomal dominant trait must be present in order to be passed on to offspring? 

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

Are my offspring at risk for Milroy disease even if I don't have any signs of the condition myself?

When a genetic disorder is diagnosed in a family, family members often want to know the likelihood that they or their children will develop the condition. This can be difficult to predict in some cases because many factors influence a person’s chances of developing a genetic condition. One important factor is how the condition is inherited. Milroy disease is inherited in an autosomal dominant manner. Most individuals diagnosed with Milroy disease have an affected parent. However, some people with a disease-causing mutation never develop any health problems (reduced penetrance) or may experience only mild symptoms (variable expressivity) of the disorder.[1]

Estimating the chance of developing or passing on a genetic disorder can be complex. Genetics professionals can help people understand these chances and help them make informed decisions about their health.  
Last updated: 7/29/2011

How is Milroy disease inherited?

Milroy disease is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In many cases, an affected person inherits the mutation from one affected parent. Other cases may result from new mutations in the FLT4 gene. These cases occur in people with no history of the disorder in their family. About 10 percent to 15 percent of people with a mutation in the FLT4 gene do not develop the features of Milroy disease.[2][3] In some families, the history may appear to be negative because of failure to recognize the disorder in family members as a result of reduced penetrance or variable expression.[3] Reduced penetrance and variable expressivity are factors that influence the effects of particular genetic changes. These factors usually affect disorders that have an autosomal dominant pattern of inheritance, although they are occasionally seen in disorders with an autosomal recessive inheritance pattern.[1]
Last updated: 7/29/2011

What is reduced penetrance?

Penetrance refers to the proportion of people with a particular genetic change (such as a mutation in a specific gene) who exhibit signs and symptoms of a genetic disorder. If some people with the mutation do not develop features of the disorder, the condition is said to have reduced (or incomplete) penetrance. Reduced penetrance probably results from a combination of genetic, environmental, and lifestyle factors, many of which are unknown. This phenomenon can make it challenging for genetics professionals to interpret a person’s family medical history and predict the risk of passing a genetic condition to future generations.[1]
Last updated: 7/29/2011

What is variable expression?

Although some genetic disorders exhibit little variation, most have signs and symptoms that differ among affected individuals. Variable expressivity refers to the range of signs and symptoms that can occur in different people with the same genetic condition. As with reduced penetrance, variable expressivity is probably caused by a combination of genetic, environmental, and lifestyle factors, most of which have not been identified. If a genetic condition has highly variable signs and symptoms, it may be challenging to diagnose.[1]
Last updated: 7/29/2011

Is testing available for Milroy disease?

Yes. GeneTests lists the names of laboratories that are performing clinical and research testing for Milroy disease. Clinical genetic tests are ordered to help diagnose a person or family and to aid in decisions regarding medical care or reproductive issues. If the disease-causing mutation in a family is known, molecular genetic testing of at-risk relatives ensures identification of those who will benefit from treatment early in the disease course and identifies unaffected heterozygotes who warrant genetic counseling as their offspring are at a 50% risk of Milroy disease.[3] Talk to your health care provider or a genetic professional to learn more about your testing options. 

You can learn more about the difference between clinical and research testing at the following information page developed by the Genetic Home Reference.
Last updated: 7/29/2011

How can I find a genetics professional in my area?

Genetics clinics are a source of information for individuals and families regarding genetic conditions, treatment, inheritance, and genetic risks to other family members. More information about genetic consultations is available from Genetics Home Reference. To find a genetics clinic, we recommend that you contact your primary healthcare provider for a referral.

The following online resources can help you find a genetics professional in your community:

Last updated: 1/21/2014