Blood samples are collected for two different research reasons: protein studies and DNA (genetic) studies.
Up to 40% of individuals with Frontotemporal degeneration (FTD) have a very strong family history of FTD or other neurodegenerative conditions, and we know about the genetic changes that cause FTD in about half of these individuals. Blood is an excellent source of DNA, the genetic material that is present in all of the cells of every individual. The blood sample is processed in a laboratory to collect a sample of DNA. Once this DNA is collected, it can be examined in our laboratory to study known genetic causes of FTD. The DNA can be analyzed to see if an individual has any of these known genetic causes. If a known genetic cause is found, we can report this information back to the patient and his/her family, if desired, and our genetics counselor can provide genetic education and counseling about the genetic result. Researchers at the University of Pennsylvania and at other laboratories throughout the world are working to discover new genetic factors that are important in FTD.
We are also interested in discovering genetic factors that can influence the risk or progression of FTD symptoms, as well as genetic factors that might help to predict an individual’s response to certain treatments or medications. Genetic factors such as these can be very difficult to find and it can take thousands of DNA samples in order to make these types of discoveries.
The majority of individuals with FTD do not have an inherited condition, and FTD in non-genetic cases is said to be sporadic. Blood tests can be potentially helpful in detecting and diagnosing sporadic FTD. By studying the types and levels of FTD-related proteins in blood samples, researchers hope that a diagnostic test for FTD can be developed. The study of FTD-related proteins in blood may also provide insight into the progression of the disease. For example, in clinical treatment trials, a blood test can potentially help provide evidence that the disease process is slowing or stopping in response to the new medication. Unfortunately, the development of blood tests for FTD is very challenging because protein levels in the blood are affected by many body processes, not only the brain. Researchers at the Penn FTD Center are studying the development of new blood tests for FTD.
Cerebrospinal fluid (CSF) is a clear, water-like fluid that surrounds the brain and spinal cord. CSF is constantly being produced in the brain and plays an important role in keeping the brain and spinal cord healthy. While about 150cc of CSF surrounds the brain and spinal cord, we make about 500cc (half a liter) of CSF each day. Because CSF is produced in the brain and bathes the brain tissue, it shares many biological characteristics of brain tissue. For this reason, CSF is extremely important in making an accurate diagnosis of the cause of an individual’s neurological symptoms. This is valuable because other neurodegenerative conditions such as Alzheimer’s disease can mimic FTD in up to 30% of cases. A lumbar puncture (or spinal tap) is a very routine and safe clinical procedure for obtaining a sample of CSF. By comparison, taking a biopsy sample of a living patient’s brain tissue is more invasive and carries many more risks. In a laboratory, the CSF can be analyzed for many of the same protein abnormalities that are found in the brain tissue of individuals with FTD. A CSF test for Frontotemporal degeneration is helpful not only for making the initial diagnosis, but may also provide essential information about the progression of FTD during a clinical treatment trial. At the Penn FTD Center, we are world leaders at analyzing CSF samples. Our researchers are investigating the development of new and more accurate CSF tests for specific forms of FTD.