Ask The Doctor/q& a With Dr Rebecca Gilbert
My Dad had Parkinsons disease, and I just learned that my Grandma his mother also had PD. I do not currently have any symptoms of PD, but should I get genetic testing?
This is actually a very complicated question, as there are a number of genes that have been associated with PD, but most people with PD do not have one of the currently identified genetic mutations. If someones father and paternal grandmother have PD, that makes it more likely that an identifiable genetic mutation is involved, although you might not have inherited it. In addition, most PD mutations have what is called reduced penetrance, which means that only a subset of people who inherit the mutation actually manifest the disease. Currently, it is not standard of care for someone who does not have any symptoms of PD to get genetic testing.
For someone who already has PD, the answer about whether to get genetic testing may be different. There are clinical trials that are ongoing now and others that are set to start which are investigating treatment of PD in people who carry specific mutations. Genetic testing of potential participants in the trials is therefore necessary. If one of these trials is successful in treating PD associated with a specific genetic mutation, that will of course change the whole landscape of genetic testing for PD and make it much more widespread.
Since the topic is not straightforward, I wrote a blog addressing it which you may find helpful. You can read it here.
Faqs: Genetics & Parkinsons
If I have Parkinson’s disease will my child get it too? Will I inherit Parkinson’s if my parent or grandparent has it?
Most people with Parkinson’s have no known genetic link. Their children will likely never develop Parkinson’s. There are some known genetic variations that increase the risk of getting Parkinson’s, but most people with these variations do not get Parkinson’s. Like many other diseases, Parkinson’s is a result of a complex interaction between genes and environmental factors.
In a small number of people , Parkinson’s is inherited and can affect multiple family members. Their children may have a higher risk of developing Parkinson’s. However, there is no guarantee they will develop PD.
What if my genetic test is positive for a Parkinson’s gene?
Scientists have identified several genetic mutations that can increase the risk of developing Parkinson’s. If someone tests positive for a mutation in a Parkinson’s gene, it does not necessarily mean they will develop PD. Some people who have mutations in the genes associated with Parkinson’s never develop PD. A person may inherit a hereditary genetic mutation that increases their risk for Parkinson’s however, they may also inherit other genes, be exposed to environmental factors or have lifestyle choices that offset the risk. Genetic testing is currently available for the following genes related to Parkinson’s: GBA, PARK7, SNCA, LRRK2, parkin and PINK1.
What can I do with my genetic test results?
Genetic Testing May Lead To A Cure
Although genetic testing can leave individuals with many unanswered questions, the data provided may further the study of the disease.
The more individuals you can work, the more things you can discover, says Cannon. We are interested in studying people who have a risk gene because the sooner we can learn how to stop it , the better off people will be.
Clinical trials are in progress to test therapies that target gene mutations, in particular GBA and LRRK2. Pharmaceutical companies conducting these studies need patients who test positive for specific gene variations. By getting tested, individuals have a chance to participate in research programs that may lead to a cure.
Gilbert points out that drugs that target specific mutations may benefit a larger group of Parkinsons patients.
The biochemical problem that happens when a person has an LRRK2 mutation might appear in someone else without an LRRK2 mutation but by another means, she says. So they may also benefit from medication developed for people with an LRRK2 mutation.
If you are interested in participating in a trial, the Michael J. Fox Foundation offers a roundup of the latest investigations currently being conducted and how to get involved.
Also Check: Parkinson’s Quality Of Life
Can Parkinsons Be Passed From Parent To Child
Its rare for Parkinsons disease to be passed down from parent to child. Most cases of Parkinsons arent hereditary. But people who get early-onset Parkinsons disease are more likely to have inherited it.
Having a family history of Parkinsons disease may increase the risk that youll get it. This means that having a parent or sibling with Parkinsons slightly increases the risk.
In most cases, the cause of Parkinsons disease remains unknown. But researchers have identified multiple risk factors that can increase your chances of getting this disease.
Risk factors for Parkinsons disease include:
- mutations in specific genes associated with Parkinsons
- having a family history of Parkinsons or a first-degree family member with Parkinsons
- being older, especially above the age of 60
- exposure to herbicides and pesticides
- being assigned male at birth
- history of brain injury
How Often Does Parkinsons Run In The Family
Most Parkinsons cases have no connection to a genetic cause, but scientists have found that some gene mutations can heighten an individuals risk. Researchers believe that a better understanding of these genes may improve ways of identifying and treating the illness.
The National Institute of Neurological Disorders and Stroke reports that an estimated 15 to 25 percent of people with Parkinsons have a family history of the disorder. The Michael J. Fox Foundation for Parkinsons Research estimates that about 10 percent of cases are linked with a genetic cause.
Parkinsons doesnt stand out as a hereditary disease over and above any other chronic diseases that people deal with, says Rebecca Gilbert, MD, PhD, chief scientific officer for the American Parkinson Disease Association in New York City. But if you have a parent with Parkinsons disease, you have about a fourfold greater risk over the general population.
Still, that risk is relatively small. About 1 percent of the population over 60 has Parkinsons, according to the Michael J. Fox Foundation, and that number rises to about 4 percent for those who have a mother or father with the illness, according to Dr. Gilbert. The overall message is: Just because you have a gene linked to Parkinsons does not mean you will get the disease.
Also Check: Music Therapy For Parkinson’s
Can Frontotemporal Dementia Be Inherited
Sometimes, yes. FTD is relatively rare compared with Alzheimers disease or vascular dementia, but it can be passed on directly from parent to child. A diagnosis of FTD can therefore cause a great deal of worry to someone who has children or grandchildren.
Most FTD is not directly inherited, but about 40 per cent of people who develop the condition will have at least one close relative diagnosed with some kind of dementia. This can include FTD, Alzheimers disease or amyotrophic lateral sclerosis . In general, the greater the number of relatives who have had dementia particularly FTD or ALS the greater the chances of developing familial FTD.
Of the different types of FTD, the behavioural form is the one that is inherited most often. The type of FTD which starts as primary progressive aphasia is only rarely inherited.
There are lots of different genes causing familial FTD, each with its own pattern of inheritance. If you are concerned about either passing on an FTD gene or inheriting the disease from your parents, you can ask your GP to refer you to a genetic testing service in your area. These people are specially trained to guide you through the process of finding out whether you have a gene that causes FTD. You can also get in touch with a specialist support group at Rare Dementia Support, who can provide information and advice about how to cope with having a heritable form of FTD in your family.
Take Care Of Yourself
Probably one of the most important, and sometimes difficult, things caregivers can do is to take care of themselves. This includes maintaining mental and physical health by making and keeping your own medical and dental appointments. As a caregiver, it is important to keep your job whenever possible as it provides not only financial help and possibly insurance coverage, but also a sense of self-esteem. Join a support group for caregivers if possible. Support groups help you meet people who are going through what you are going though, vent frustrations, give and receive mutual support, and exchange resource information and coping strategies. Whenever possible get your sleep, take breaks, make and keep social activities, and try to keep your sense of humor.
Also Check: Types Of Parkinson’s Disease
Will I Inherit Dementia From My Parents Is It Hereditary
If youre caring for a relative living with dementia, its natural to be concerned about whether or not you or your children will develop the disease. In reality, there are actually different kinds of dementia and most of them are not hereditary.
Read on to learn about the common types of dementia, and what the chances are for people with relatives diagnosed with dementia to develop the disease.
Can Alzheimers Disease Be Inherited
In the vast majority of cases , Alzheimers disease is not inherited.
The most important risk factor for Alzheimer’s disease is age. Because Alzheimer’s disease is so common in people in their late 70s and 80s, having a parent or grandparent with Alzheimer’s disease at this age does not change your risk compared to the rest of the population.
However, if somebody has developed Alzheimers disease at an earlier age there is a greater chance that it may be a type of Alzheimers disease that can be passed on.
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Know Which Diseases Can Actually Be Inherited
The pattern of inheritance of some diseases is pretty straightforward, but for others it’s more complicated.Sometimes all it takes to develop a disease is inheriting a gene change from just one parent. This is called an autosomal dominant single-gene disorder and includes:
- Huntington disease
- Neurofibromatosis type 1
If you have one of the diseases above, there’s a 50% chance it will be passed on to each of your children.
Other times, both parents have to contribute a change in the same gene in order for a child to develop the genetic condition. This is called an autosomal recessive single-gene disorder and includes:
- Congenital deafness
- Tay-sachs disease
A recessive single-gene disorder is often passed on by parents who don’t know they carry the disease. If both parents are a carrier of a disease, each of their children has a 25% chance of inheriting the disease and a 50% chance of becoming a carrier himself or herself. These diseases usually aren’t seen in each generation.Carter says that all people probably carry about 5 or more genes associated with a recessive disorder that they may not know about.Therefore, genetic testing or screening is offered to individuals who would like to know if they are carriers of recessive disorders such as those who plan to get pregnant or have a family history of inherited disease.
What Is Parkinsons Disease
Parkinsonâs disease is a progressive, neurological disease that mainly affects movement but can also affect cognition. Parkinsonâs disease results from the destruction of nerve cells in a part of the brain called the basal ganglia.
Different parts of the brain work together by sending signals to each other to coordinate all of our thoughts, movements, emotions, and senses. When we want to move, a signal is sent from the basal ganglia to the thalamus and then to the cerebral cortex, all different parts of the brain. Nerve cells in the brain communicate by using chemicals. A chemical called dopamine is produced in a group of cells called the substantia nigra and is essential for normal movement. When the cells die, they can no longer produce and send dopamine, so the signal to move doesnât get communicated. By the time a person starts to experience motor symptoms of Parkinsonâs, theyâve already lost approximately 50% of their dopamine producing cells. People may experience non-motor symptoms from loss of other neurotransmitters up to ten years before motor symptoms are noticed.
Recommended Reading: What Causes Parkinson’s Syndrome
Who Should Get Genetic Testing
Two groups might consider getting genetic testing, according to Gilbert:
- People with Parkinsons who want to know if they have a mutation they may pass along to their children
- Children and siblings of family members with Parkinsons who want to determine their genetic risk for the disease
Right now its not standard of care for everyone with Parkinsons to get genetic testing, she says. The likelihood that were going to find one of these mutations that is known already is small, and even if you have a mutation associated with Parkinsons, it doesnt mean that youre going to get the disease.
So, at this point, the value of getting tested depends on the individual. Doctors can provide this type of genetic evaluation, or people may turn to direct-to-consumer genetic testing, such as 23andMe. These tests, however, can be limited.
You have to be careful with those panels because theyre not very comprehensive, says Gilbert. They may test for only one or two gene variations.
Currently, 23andMe analyzes DNA from spit samples for a variant in LRRK2 and a variant in the GBA gene associated with the disorder. The company makes it clear that the exam does not diagnose the disease, and there are many other mutations to consider.
Parkinsons patient Paul Cannon, PhD, who works for 23andMe as its Parkinsons research community manager, took the test and found that he had neither of the genetic variations.
Some Inherited Diseases Are More Complicated Than Your Genes
For most diseases that “run in the family,” it takes more than inheriting just one change in a gene. Diseases and disorders with complex inheritance patterns include:
- Alzheimer’s disease
- Thyroid disorders
“These diseases are influenced by both genes and a number of other factors, such as your environment, lifestyle and diet,” says Carter.
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Talk To Your Doctor To Determine Your Risk
If three of more close relatives on one side of your family have, or had, one of the diseases above, be sure to tell your doctor.Depending on your family history, your doctor may recommend:
- Changes to your environment, lifestyle and diet that can reduce your risk
- Earlier and more frequent disease screenings
- Genetic counseling
Is Parkinsons Disease Hereditary
Family history plays a role in a small percentage of cases, but environmental factors and age also heighten the risk.
Parkinsons disease is a degenerative nerve system disorder that affects more than 10 million people worldwide, according to the Parkinson’s Foundation. It is the second most common neurodegenerative disease after Alzheimer’s, notes the National Institute of Neurological Disorders and Stroke.
Each year, 60,000 Americans are newly diagnosed with Parkinsons. While it is more common among older adults, those as young as 18 years old can get it.
The disease is especially problematic because it is difficult to diagnose and treat. Although therapies can alleviate the symptoms, there is no known cure.
Telltale symptoms, such as tremors and problems with balance or walking, may indicate that a person has the disorder, but an absolute diagnosis can only be made through an autopsy after a patient has died, according to the American Parkinson Disease Association. Parkinsons conditions can also mimic other diseases, so misdiagnosis is common, notes the Cleveland Clinic.
Foster A Good Relationship
Lastly, maintaining your relationship and communication with the person with Parkinsonâs can be the most challenging and rewarding aspect of caregiving. As Parkinsonâs disease progresses, the roles change and the person with Parkinsonâs may go from being an independent head of the household to a very dependent person requiring a significant level of care. However, research shows that despite high levels of strain, caregivers with good quality relationships have reduced depression and better physical health. Remember, as a caregiver your service to your loved one is beyond measure in terms of love, depth of care, and concern.
Tsuang: Family 1 And Family 2
We have previously described two unrelated families. Family 1 consists of eight affected individuals across two generations. One of the affected individuals was clinically evaluated. Five affected individuals were determined to have parkinsonism four were determined to have psychosis and all eight exhibited dementia as the presenting symptom. Parkinsonian signs and symptoms in this family included cogwheel rigidity, stooped posture, and bradykinesia. Dementia symptoms included forgetfulness, word-finding difficulty, impaired judgment, poor executive function, and behavioral changes. Psychotic symptoms included visual hallucinations in two individuals, and paranoid ideation in two other individuals.
Three autopsies were performed. All autopsied individuals had dementia, parkinsonism, and psychosis. Microscopic findings in one individual demonstrated sufficient senile plaque and neurofibrillary tangle pathology to meet neuropathological criteria for AD. In this same case, alpha-synuclein-positive LBs were detected in the amygdala only. Therefore, this individual may represent a case of amygdala-predominant DLB, a subtype that has been described elsewhere and the significance of which remains unclear. The other two individuals had no significant gross findings, and the substantia nigra appeared to be well-pigmented. However, on microscopic examination, these individuals exhibited LBs in the substantia nigra and the neocortex, with only mild AD pathology .
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