New diagnosis of KCNQ2-related epilepsy?

genetics, KCNQ2, research No comments
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Seven questions to ask a genetic counselor

(Updated 3/20/17)

Boston genetic counselor Lacey Smith, MS, CGC, shares the most common questions she hears from families.

I have been a genetic counselor in the Epilepsy Genetics Program at Boston Children’s Hospital for about three  years.  During my time here, I have met with many families who have received a genetic diagnosis for their child’s epilepsy, including KCNQ2-related epilepsy. Getting such a diagnosis can be overwhelming for families, as there is often a lot of information coming in at once. My hope is to provide you with answers to some of the questions I am most often asked by families when they first hear that their child has KCNQ2-related epilepsy. Even though your child has this diagnosis, each individual is unique so your experiences may be different from those of other families you may have met who also have a child with KCNQ2-related epilepsy.

The spectrum of features associated with KCNQ2-related epilepsy is quite vast and the genetics aspect is often unique to each family, so my answers may be a little vague and may not touch upon your specific needs or experiences.  As such, I am also providing suggestions of whom to contact to gather additional information specific to your child.  You can also use this information as a guide in coming up with questions to ask your child’s neurologist.

 

What does a diagnosis of “KCNQ2-related epilepsy” mean?

This means that your child has an alteration (also called a “variant”) in a gene called KCNQ2, and that variant has likely caused your child to develop seizures or epilepsy.  It may also explain any developmental challenges your child may have.

Knowing the underlying genetic cause of your child’s epilepsy could be beneficial in a number of ways.  First of all, it provides an answer or a reason as to why your child developed seizures.  Having a diagnosis can allow your child’s doctor to provide you with more information regarding prognosis and potential treatment options than they would have been able to without knowing the underlying cause.  It can prevent your child from undergoing additional unnecessary tests to rule out other conditions or medical complications. It can provide insight into family history if there are any other family members who have/had seizures and it can provide information regarding the likelihood of having another child with similar symptoms.

Click here for a handy infographic on the basics of KCNQ2

What does this diagnosis mean for my child’s prognosis?

Knowing that your child has a variation in the KCNQ2 gene can allow your child’s doctor to have a better idea of how your child’s symptoms may progress over time, based on what is already known about other children who have KCNQ2-related epilepsy.  There are two general categories of symptoms. Children usually fall somewhere along a spectrum from Benign Familial Neonatal Epilepsy (BFNE) on the mild end to an epileptic encephalopathy.  In the world of epilepsy, “benign” usually means that seizures are expected to resolve over time or the child may “grow out” of their seizures.   An epileptic encephalopathy is a term that is used when a child has seizures, and in addition, the electrical activity of the brain both during and between seizures can also cause developmental delays and cognitive challenges.

So how does one know where along the spectrum their child will be?  Unfortunately, this is difficult to know.  Currently, this isn’t enough information available to predict exactly what symptoms a child will develop based solely on the results of the genetic test.  Even among individuals who have the same KCNQ2 variant, each individual can have different symptoms. There are likely other factors (such as other genes) that are modifying the effects of the KCNQ2 variation.  Researchers are trying to learn more about these contributing factors.  In the meantime, your child is going to tell his or her own story.  Most often, the best predictor for how your child will do is how your child has done/is doing.  This can be difficult when the diagnosis comes at a very young age and there is little developmental history to look back on.

…your child is going to tell his or her own story. –LS

Over time, researchers will hopefully gain a better understanding of features associated KCNQ2-related epilepsy.   By gathering information from many individuals who have been diagnosed, they can begin to analyze patterns including the spectrum of symptoms and look for any associated modifiers to be able to better predict a child’s prognosis.  One of the ways in which researchers can collect this information is through a patient registry.  A registry gathers and keeps information about people who have a certain condition to support and encourage research into that condition.  Individuals may sign up or enroll in a patient registry to have their information included and available to researchers.  The RIKEE Project is one patient registry that is targeted specifically to KCNQ2-related epilepsy.

Register your child in RIKEE to connect with the international team of KCNQ2 researchers and advance understanding of KCNQ2-related epilepsy.

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How does this diagnosis affect management/treatment for my child?

This diagnosis may not lead to a drastic change in management.  For example, if your child has been experiencing some delays in development and has been receiving services to help with development, then he or she would continue to receive those services.  If your child is on target for all milestones, then you will know to be on the lookout for any delays moving forward and intervene right away with evaluations and/or services if needed.

You may find that your child’s doctor may not recommend any medication changes based on this diagnosis, especially if your child’s seizures are well-controlled. Targeted treatments for genetic forms of epilepsy is a very big topic in research right now– being able to treat the exact cause of seizures based on the underlying genetic cause is on the horizon and new advancements are happening quite frequently. This is true for KCNQ2-related epilepsy. Because the field is evolving so rapidly, it is best to discuss medication management with your child’s doctor in order to have the most up-to- date information.

If this is “genetic,” does it mean that one of us parents passed this on to our child?

Not necessarily.  Just because a condition is considered “genetic” does not necessarily mean it was inherited.  Genetic variations can be passed through families, or these variations can arise for the first time in a child (these are called “de novo” variants).  De novo variants are likely produced by a spontaneous event during the formation of the sperm or the egg cell.  Some individuals can have the KCNQ2 variant but never develop any symptoms, so it is possible for a child to inherit the variant from a seemingly unaffected parent.  You can determine whether your child has an inherited variant or a de novo variant by testing both parents.  Your child’s doctor can help facilitate such testing.

 

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What does this mean for my other child/children?  Can I test them?

If you have another child who also has seizures, then it is possible that they could also have the same KCNQ2 variant and it would be possible for this child to have genetic testing.  In general, it is not routinely recommended that unaffected children (children who do not show any features of the condition) undergo testing.  Rather, that child could make the decision to undergo testing on their own when they are of suitable age.

 

What are the chances of having another child with this condition?  Can I reduce the chances?

The likelihood of having another child that has the KCNQ2 variant depends on whether this was an inherited variant or a de novo variant.  If the KCNQ2 variant was inherited from a parent, then there would be a 50% (1 in 2) chance that each conception would also inherit the KCNQ2 variant.  If the KCNQ2 variant was de novo, then the chances are much smaller although not zero.  This is because there is some residual chance to have another child with the same variant due to something called “gonadal mosaicism.”  Gonadal mosaicism is not something that is routinely tested for in the clinical setting. For some families, during the parental testing process, the KCNQ2 variant is detected in some, but not all, of the cells in one of the parents. This is another form of mosaicism. For those families, it is also possible for future pregnancies to also have the KCNQ2 variant.

Regardless of inheritance of the variant it is possible to test future pregnancies to see if the KCNQ2 variant is present. For more information regarding prenatal testing options, you can speak with a genetics specialist when you are considering having additional children.

It is also important to remember that individuals with KCNQ2 variants or KCNQ2-related epilepsy may show different symptoms, even when they have the same variant.  While it is possible to test pregnancies for the KCNQ2 variant, one cannot predict with certainty the severity of symptoms an individual may present with.  Future children who have the KCNQ2 variant may have symptoms that are less severe or more severe than those of your child.

 

Who else can I talk to?

It is important to find a neurologist or epileptologist with whom you/your child feel comfortable.  Don’t be afraid to ask for a second opinion, or more!  If you have concerns regarding your child’s development, you could have your child evaluated by a neuropsychologist.  A neuropsychologist is a doctor who, through a series of tests, can identify your child’s strengths and weaknesses in learning, emotions and behavior.  From there, recommendations for services specific to your child’s needs can be made.

It may be helpful to speak with someone who has specific training with genetic conditions, whether it be specifically genetic forms of epilepsy or more general genetic conditions.  This could be a geneticist and/or a genetic counselor.  Healthcare providers who are specially trained in genetics can provide information regarding inheritance patterns, identifying family members who could be tested and options for testing future pregnancies, if desired.  You may consider asking your child’s doctor to refer you to a genetics specialist in your area.  You or your child’s provider can also find a genetic counselor through the National Society of Genetic Counselors website at www.NSGC.org, and navigate to the “Find a Genetic Counselor” link.  You can identify genetic counselors in your area and genetic counselors that specialize in epilepsy or neurogenetics.

Lacey Smith, MS, CGC

Lacey Smith, MS, CGC

Lacey Smith, MS, CGC, is a genetic counselor in the Epilepsy Genetics Program at Boston Children’s Hospital.  She has roles in both the clinic and in research.  In the clinic, she works closely with epileptologists in meeting with children who either have, or are presumed to have, a genetic form of epilepsy.  She reviews all aspects of genetic testing, discusses potential implications for other family members and future children, and helps families understand their child’s diagnosis.  In the research world, her team is trying to better understand the genetic contributions to epilepsy.  Specifically, they are trying to identify new genes associated with epilepsy, determine how variations in these genes cause epilepsy, and develop more targeted therapies for children who have epilepsy caused by variations in these genes. Lacey is also a member of EpiGC, a consortium of genetic counselors whose mission is to promote access to quality genetics services for patients and families affected by epilepsy through research, public policy/advocacy, education and outreach activities.