Genetics and Epilepsy
I thought we inherited different traits because of our chromosomes. What is the difference between genes and chromosomes?
An easy way of thinking about a chromosome is as a "package" filled with many genes.
The human body is made up of millions of cells. There are many different types of cells such as brain cells, muscle cells, and skin cells. Most cells in the body contain chromosomes. Each of these cells holds 23 pairs of chromosomes (46 total). One member of each pair is inherited from the mother and the other from the father. Genes are located on chromosomes and, thus, are passed from both parents to the child.
Genes, in turn, are made up of a substance called DNA (deoxyribonucleic acid). Genes give the cell instructions to make proteins, which are necessary for the body to do all the things that it does.
That sounds so complicated. What if something goes wrong?
It is complicated. Genes can be altered in many ways. Changes in the DNA that cause a protein to not work normally or stop working altogether are called "mutations." Environmental factors can also affect the way cells work.
Some mutations may result in disease and some of these conditions can be passed on to future generations.
Is epilepsy inherited?
Some types of epilepsy are. Epilepsy is not a single disorder, but a collection of many disorders that all have in common the tendency to cause a person to have seizures. When individual characteristics are caused by single genes, they are called "simple" genetic traits. Only a few rare types of epilepsy are caused by alterations in single genes. Most seem to be caused by a complex interaction among multiple genes and environmental influences.
I'm pregnant and I have epilepsy. Is my baby likely to have seizures, too?
Certain types of epilepsy do seem to run in families. Some studies have shown that the risk of epilepsy in brothers, sisters and children of people with seizure disorders ranges from 4-8% (that is, between about 1 in 25 and about 1 in 12). The risk in the general population is about 1-2% (between 1 in 100 and 1 in 50). However, it's important to remember that although the risk is higher than in the general population, most people with epilepsy do not have any relatives with seizures, and the great majority of parents with epilepsy do not have children with epilepsy.
Which types of epilepsy are most likely to be inherited?
People who have a generalized epilepsy (one where the EEG pattern shows both sides of the brain involved at the beginning of a seizure) seem somewhat more likely to have other family members with seizures than those with a localization-related epilepsy (also called partial or focal, where the EEG pattern shows seizures beginning in a single area of the brain). Parents with a history of generalized absence (childhood petit mal) seizures are more likely to have children with the same condition than those with other generalized seizures or focal seizures.
What are some of the other factors that seem to be involved in inheritance?
- Age when epilepsy begins -- Children of people whose seizures started early in life (for example, before 20 years of age) have a greater risk of developing epilepsy than children of people whose seizures started later in life.
- Mothers and fathers with epilepsy -- Studies have shown that the risk of epilepsy is about twice as high in children of women with epilepsy than in children of men with epilepsy. Research has shown that this is not related to pregnancy or birth complications, maternal seizures during pregnancy or maternal antiepileptic drugs during pregnancy. More research is needed to explain this difference.
- Cause of epilepsy -- The risk for developing epilepsy does not seem to be increased, compared with the general population, in relatives of people who have epilepsy caused by serious brain injury that occurs after birth due to conditions such as strokes, brain tumors, severe head trauma or brain infections.
Can epilepsy skip a generation?
Yes, it can. As discussed earlier, most types of epilepsy are caused by multiple genes and environmental influences. Not everyone who carries genes that make him or her more likely to develop epilepsy will, in fact, do so. Therefore, even if the genes are passed on, not every generation in a family will have seizures.
How can I find out what the risk is for my baby to inherit my type of epilepsy?
Ask your physician to refer you for genetic counseling. Specially trained physicians or nurses, genetic counselors, and other health care professionals can help you study your medical history, find out facts about your family history and, if possible, calculate the risk for you and your baby. They may recommend certain laboratory tests to get more information.
It's important to remember that although there is a lot of evidence that genes play an important role in causing epilepsy, exactly which genes are involved has not been identified for most people who have seizures. Studying the families of people who have epilepsy will help increase our knowledge and perhaps, in the future, will lead to new treatments for epilepsy or even measures to prevent epilepsy.
If more than one member of your family has a history of epilepsy or seizures, please consider participating in the Foundation's Gene Discovery Project. Completion of a confidential online questionnaire by you or a family member will allow scientists to determine whether the pattern of epilepsy found in your family could be valuable for further study. Your participation may help lead to exciting new discoveries about genetics and epilepsy.
Health Issues After Your Baby is Born
Will my seizure pattern change after I have my baby?
That's unpredictable. Some women with epilepsy have changes in their seizures while they are pregnant. During pregnancy, concentrations of your antiepileptic drug (AED) may change or decrease, putting you at greater risk for seizures. Your physician may increase your seizure medication for better seizure protection.
After your baby is born, your hormones change and medication levels in your bloodstream tend to rise, increasing the possibility of side effects. These factors may make it necessary for your physician to check medication blood levels more frequently in the first few months after delivery. Keep in close contact with your physician during this time until your body returns to its pre-pregnancy state.
Stress and lack of sleep make my seizures worse. I'm worried about taking care of my baby.
Every parent has to think about this. Women who have just had a baby will have disturbed sleep, extra work and stress, and hormonal changes -- and for a woman with epilepsy these factors can increase the risk of seizures. Include other family members and friends in the care of your baby, to give you a chance to rest. As a parent, during pregnancy and after delivery, the best thing you can do for your baby is to take good care of yourself. Get enough sleep, eat well, exercise regularly and take your prescribed seizure medication. Talk over any problems with your neurologist and your primary health care provider, and get their advice about any necessary adjustments in your lifestyle.
Also, see the section of the Answer Place on Parenting Concerns for the Mother with Epilepsy.
I want to breast-feed my baby. Will that be safe?
For most women with epilepsy, breast-feeding is a safe option. All seizure medications will be found in breast milk, but this usually does not affect the baby who has been exposed already to the mother's medication during pregnancy.
Talk with your doctor about your medications and breast-feeding, particularly if you are taking phenobarbital (Luminal), primidone (Mysoline), or benzodiazepines (valium, lorazepam, and clonazepam). Women who breast-feed while taking these medications will need to watch their baby carefully for any signs of excessive sleepiness or irritability. If your baby fails to gain weight because it is too sleepy to eat, you will need to follow up with your child's pediatrician, the nurse, or a lactation (breast-feeding) consultant recommended by the doctor about switching to formula. A combination of breast and bottle may be an option depending on your baby's symptoms. If you consult a breast-feeding specialist, this individual will work with your child's pediatrician, the nurse, and you to determine the best approach. You may be asked to keep careful records of the time of each feeding and the number of minutes your baby breast-feeds, as well as voidings and stoolings so the doctor can evaluate how much nourishment your baby is getting.
Continuing to take your prenatal vitamins is important if you breast-feed and if you plan on having another baby.
While you are pregnant, it's a good idea to learn as much as you can about breast-feeding and about resources in your community so you'll know what to expect and what supports are available to you.
What if I have a seizure while I'm holding the baby?
There is no way to ensure that you won't have a seizure while you are caring for your new baby. But you can always have a plan to protect the baby if a seizure occurs. If you have a warning before you have a seizure, you can maintain a secure area in each room of your house where you can safely lay the baby down if you feel a seizure coming on.
Some women don't experience an immediate warning before a seizure, but they may feel a bit strange for several hours earlier. If this describes you, you may want to have a friend or family member stay with you during a day when such a feeling occurs.
Whether or not you have one of these warnings, you can minimize the risk of potential harm to your baby by taking the following precautions whenever the two of you are alone:
- If you use a changing table, make sure your baby is always strapped in. Or you may want to change your baby's diapers and clothing on the floor.
- Never give your baby a bath by yourself. Make sure someone else is with you in the room.
- Always fasten the safety straps whenever you put your baby in an infant seat, even if you intend to be right there.
- If you do not have grand mal or other falling-type of seizures, you may want to use a cloth-front baby carrier whenever you are walking or standing and holding your baby.
- When feeding your baby, you may want to use an infant seat, or use pillows to make a comfortable seat on the floor.
- Never hold your baby while cooking, ironing, or carrying hot liquids.
Family members may also be able to help you during the night, by taking turns with feedings. Some mothers who breast-feed extend their sleeping time by pumping breast milk into bottles and then refrigerating it, so another family member can feed the baby at night.
At least one study has shown that seizures are more likely to occur in the period following birth, known as the postpartum period. The processes of labor and delivery have stressed your body. It's hard to find time to rest. You may be excited and anxious. Your hormones are changing. All of this contributes to stress, and sometimes to sleep difficulties as well.
During this period your neurologist will want to check your antiepileptic drug levels to make certain they're within a range to protect you from having seizures. You will also want to make sure that those levels are not too high. Your doctor or nurse will be able to explain the symptoms of high drug levels. Even though you are taking the same amount of medication as you were before your delivery, those levels can rise during the postpartum period. This is why it is so important to continue to see your neurologist regularly.
What about night-time feedings and getting enough sleep?
Breast-feeding is good for your baby and good for you, but it may create more demands on you, especially at night with loss of sleep. Keep the baby next to your bed at night, and feed her in bed with you. Whenever you are feeding your child, sit or lie down -- this is a perfect time to put your feet up and relax. If there is concern that loss of sleep may trigger seizures, breast milk can be pumped in advance and used for night-time feedings by your partner or another family member. Having a family member feed the baby at night is ideal but not always possible.
If you are alone and bottle-feeding, don't carry the baby to the kitchen -- leave your baby in the crib while you prepare the bottle and bring it back with you.
I have heard a lot recently about postpartum depression. Is that something I need to think about?
Women with epilepsy experience the same emotional adjustments as other women after having a baby. Be sure to discuss any changes in mood with your doctor, particularly if they continue or recur over time and if they prevent you from carrying out your normal routine.
I'm concerned about getting pregnant too soon after I have my baby. What can I do to prevent an unexpected pregnancy?
It's a good idea to think about this. Breast-feeding and the expected hormonal changes in the months right after having a baby can make birth control complicated for any woman. Work with your neurologist and your gynecologist/obstetrician to choose the birth control method that is most appropriate for you.