Parkinson's Disease: Genetic Risk Factors, Family History and Research

Thursday, April 04, 2013 11:47 AM comments (0)

April is National Parkinson’s Disease Awareness Month. All this month, we will feature a series of posts addressing Parkinson’s disease symptoms, genetics, treatment options and more from NorthShore neurologists—Demetrius Maraganore, MD, Aikaterini Markopoulou, MD, and Ashvini Premkumar, MD— to raise awareness about this common and often disabling neurological disorder.

by Demetrius Maraganore, MD:


laboratoryAre the children of a parent with Parkinson’s disease likely to inherit the disease? Is there a greater risk if the father or the mother has the disease?

My research team conducted family studies that defined the risk of inheriting Parkinson’s disease. The children of Parkinson’s disease patients carry a two-fold risk for Parkinson’s disease. They are twice as likely to get Parkinson’s disease compared to the children of persons without Parkinson’s disease. However, one needs to consider that the lifetime risk for Parkinson’s disease in the general population is 2%, so the risk of Parkinson’s disease for the children of a patient is 4%, or twice the baseline risk for the general population. That’s a pretty low risk and I wouldn't recommend any specific lifestyle changes or preventive therapies for the children of patients with Parkinson’s disease.
 
That said, about 5% of Parkinson’s disease cases are due to an inherited gene abnormality (mutation). In families where multiple members have Parkinson’s disease, the risk may be as great as 50% to the children of an affected person. When there are multiple family members with Parkinson’s disease, I refer patients for genetic counseling and in some instances we also perform genetic testing. 

What are the most important genetic risk factors for Parkinson’s disease?

There are two types of genetic factors that are important to Parkinson’s disease: 1) genes that rarely cause familial Parkinson’s disease (multiple affected members in the same kindred), and 2) genes that are not causal but that slightly increase the risk for Parkinson’s disease in populations worldwide (susceptibility genes). About a dozen genes have been identified as rare causes of familial Parkinson’s disease, and about a dozen genes have been identified as common risk factors in populations worldwide. The causal gene mutations are rare, accounting for less than 5% of all Parkinson’s disease cases. The susceptibility gene variants are common—e.g., occurring in 25% of persons in the general population—but they have small effects (no more than doubling the risk for Parkinson’s disease). 

Of all of the Parkinson’s disease genes, the most important is alpha-synuclein because it is both a causal gene in some families and also a susceptibility gene in populations worldwide. In other words, rare variants (mutations) cause Parkinson’s disease in rare families, while common variations (polymorphisms) increase the risk for Parkinson’s disease worldwide.

The alpha-synuclein gene holds the code for making the protein alpha-synuclein. The protein alpha-synuclein accumulates abnormally in the brain cells of every patient with Parkinson’s disease regardless of the causes. Many scientists believe that it holds the key to understanding and curing Parkinson’s disease. Our research team at NorthShore has led many of the most important studies of alpha-synuclein and Parkinson’s disease, including studies in families and in populations worldwide. We were also amongst the first to study the interaction of alpha-synuclein with other genes or environmental factors, or to study the association of the alpha-synuclein gene with motor and cognitive outcomes in Parkinson’s disease. 

Are there genetic research studies of Parkinson’s disease at NorthShore? How can I participate?

At NorthShore we are conducting a genetic study called the DodoNA Project. We aim to discover genetic factors that predict how neurological diseases progress in severity and that predict disease outcomes. We aim to use this information to individualize the care of our patients and to halt the progression of neurological diseases. One of the diseases we are studying is Parkinson’s disease. 

We will enroll at least 1,000 Parkinson’s disease patients into the study, and follow them at least annually for several years. To be eligible for the study you need to be new to our Movement Disorders practice within the past year, a resident of Cook or Lake County and willing to provide a blood sample for DNA extraction and storage. We also require your permission to compare your genetic code with the information that we collect in your medical record.

If you wish to participate, the best thing to do is to request an appointment to be seen as a patient in the Department of Neurology at NorthShore. We can then enroll you into the study after your office visit. You can also support the DodoNA project by joining forces with NorthShore’s Auxiliary and by supporting the Hospitals’ Gala

Colorectal Cancer – Early Screening Can Save Lives

Tuesday, March 26, 2013 9:30 AM comments (0)

colon cancerColorectal cancer is one of the leading causes of cancer deaths in both men and women in the United States. However, if everyone over the age of 50 were regularly screened, it might be possible to reduce deaths associated with colorectal cancer by as much as 60 percent.

Many women believe that colorectal cancer is a disease that affects more men than women, so they might not be aware of or believe they need to follow current screening recommendations. National Colorectal Cancer Awareness Month this March is the right time to spread the word that colorectal cancer affects men and women equally and that screening saves lives.

Joel Retsky, MD, Gastroenterologist, shares some important information about colorectal cancer everyone should know, men and women:

  • Your risk increases with age. More than 90% of colorectal cancer cases occur in those who are 50 or older. Everyone over the age of 50 should follow national screening guidelines and continue screening at regular intervals at least until 75 years of age.
  • You should not wait for symptoms. Colorectal cancer rarely causes noticeable symptoms in the early stages. Symptoms of colorectal cancer—bleeding from the rectum, change in bowel habits, noticeable weight loss—often do not appear until the cancer is advanced and more difficult to treat. Most colorectal cancers come from polyps, or abnormal masses, that grow in the inner lining of the large intestine. With screening, polyps can be removed before they even become cancerous.
  • Family history is important. If you have a family history of colorectal cancer, you may need to begin screening earlier, perhaps at 40 or even younger. You will also need to be screened more frequently than currently recommended by the national guidelines. 
  • Personal history is important. Some studies have shown that women who have had ovarian, uterine or breast cancer have a higher-than-average chance of developing colorectal cancer. Crohn’s disease and ulcerative colitis are also risk factors. Talk to your physician about how these risk factors might affect the frequency of your screenings.
  • There are several screening options. There are many tests for colorectal cancer, including fecal occult blood test (FOBT), sigmoidoscopy, colonoscopy, virtual colonoscopy and barium enema. Colonoscopy is the most effective test for colon cancer screening. Talk to your physician about which screening option is best for you.


If you’re 50 or over and have never been screened for colorectal cancer, make National Colorectal Cancer Awareness Month the month you schedule your first appointment.


Have you been screened for colorectal cancer?

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