How can being a carrier affect a woman’s health?

Females carriers are usually not affected with Duchenne or Becker because they make enough of the dystrophin protein. However, they can have some symptoms of Duchenne, such as changes to heart function, mild muscle weakness, fatigue (a tired feeling), or cramping in their muscles. Rarely, a carrier has symptoms that are as severe as those of a male with muscular dystrophy. The term “manifesting carrier” is sometimes used to describe a woman who has symptoms connected to a DMD gene variant.

Although rare, symptoms can be seen in young girls who are carriers of Duchenne. It is important to be aware of this risk and bring any concerns about muscle weakness, impaired balance or frequent falls, muscle fatigue, and cognitive or behavioral issues to your doctor. Learn more about young female carriers of Duchenne.

All carriers should be evaluated by a healthcare provider familiar with dystrophinopathy.

Skeletal muscles

Most carrier females (about 80-90%) have no problems with their skeletal muscles. Some have mild muscle weakness, fatigue (a tired feeling), pain, or cramping in their muscles. Rarely, a carrier has symptoms that are as severe as those of a male with muscular dystrophy. These issues should be addressed by specialists in these areas (neuromuscular specialists including neurology and/or physical medicine and rehabilitation (PM&R), physical therapists, etc.) and followed regularly. They may suggest stretches, exercises, and/or medication for pain that may be helpful.

Cardiac function

Carrier females have an increased chance of changes to heart function. It is not yet known how common heart changes are, but some studies have estimated that 10-50% of carriers have heart changes. The large majority of carriers will never need heart treatment or have health effects.

Because a small percentage of carriers may have serious heart concerns, however, it is important for all women who are carriers and women who are at risk to be carriers (for example, women with a son or brother with Duchenne) to have regular heart evaluations, beginning in their late teens/early adult years and, if normal, repeated every 3-5 years.

Women who know that they are carriers, or women who suspect that they might be carriers, should discuss heart screening with their doctors. The best screening plan is not yet known, so different healthcare providers might make different recommendations. Findings from a recent study suggest that beginning cardiac MRI in the third decade of life to evaluate for the presence of underlying cardiac disease should be considered. If there are any problems or potential problems found, the carrier may be referred to a cardiologist. If cardiac issues are found, they should be treated by a cardiologist who is familiar with heart failure and, if possible, knowledgeable about Duchenne.

Reproductive Care

It is important for carriers and potential carriers to have the best and most accurate information in order to make informed decisions about future pregnancies. Women have several reproductive choices to consider including pre-implantation genetic testing or prenatal genetic testing during pregnancy. These decisions are very complicated and personal and there is no “right answer.” Please speak with a genetic counselor if you are a carrier or if you have a child with Duchenne or Becker. A genetic counselor can review the benefits and risks for each of these procedures and discuss all of your options so you can make the best decision for you and your family. Learn more about reproductive options.

Psychological Care

Learning that one is a carrier can cause strong emotions. It is not uncommon for women to feel sad, worried, or guilty after learning that they are carriers. Although no one is in charge of which genes they pass on to their children, many women wish that they could control their genes or take back the illness.

Carriers considering having children (or more children) may be afraid of the possibility of having an affected son (or another affected son). Sometimes the fears change their plans about having children. Some women choose to have prenatal genetic testing during pregnancy. Other women choose to have children no matter what. These decisions are very complicated and personal, and there is no “right” answer.

Manifesting carriers may have additional feelings related to the uncertainty around their own health. It is difficult to predict if the symptoms in a woman who is a manifesting carrier may get worse, and if so, at what rate. It can be especially challenging for manifesting carriers who are trying to take care of an affected son while dealing with their own symptoms.

Strong feelings related to being a carrier do not happen only in families with Duchenne or Becker; they may be found along with any genetic condition. Speaking to a healthcare provider, especially a genetic counselor or psychological counselor, or other mothers in similar situations about these feelings may be helpful.

About 80-90% of carriers have no muscle symptoms. Such carriers usually do not know that they are carriers unless a family member is diagnosed with Duchenne and they have genetic carrier testing. Some carriers do have skeletal muscle, joint, or heart symptoms caused by the variant in the DMD gene. Females with germline mosaicism most likely have no increased chance for skeletal muscle symptoms or heart changes related to Duchenne. Learn more about what it means to have germline mosaicism.

Learn More About Being a Carrier

In the past, there has not been a great deal of research focused on female carriers, but this is changing. The Duchenne Registry, started by PPMD in 2007, has always collected data on female carriers. In fact, we encourage all carriers to consider joining The Duchenne Registry. Carriers should have an account for themselves as well as each child with Duchenne or Becker. Please visit the Registry website to learn more, or email coordinator@duchenneregistry.org.

The data you share will help us advance research by providing a better understanding of the impact of being a carrier, the wide spectrum of symptoms, and the significance of different types of genetic variants.