While most neurological conditions are not inherited, some, like Alzheimer's disease, epilepsy and Parkinson's disease to name a few, may run in families.
At NorthShore, genetic testing is available for these inherited neurological conditions and others. Family history, ages at diagnosis and neurological features in a family are used to determine the likelihood of an inherited neurological condition and, if one is suspected, which gene(s) should be analyzed. It is generally most informative if a relative who has had symptoms related to a neurological condition is tested first, to determine if an identifiable gene mutation exists in the family. If a mutation is identified, at-risk family members may elect to be tested for the familial mutation. Those testing positive may have a significantly increased risk of developing a specific neurological disorder, while those relatives testing negative may be told that they have the general population risk. In some instances, there are treatments available for persons testing positive to protect against or delay the onset of neurological disease.
Genetic counseling may be appropriate if you have a family history of any of the following:
Alzheimer's Disease (AD)
AD is the most common cause of dementia, causing a significant decline in memory and cognitive functions. It most often occurs after the age of 65. Less than 10 percent of these cases, though, follow an obvious inheritance pattern known as Familial Alzheimer's Disease (FAD). This rare form of Alzheimer's disease usually occurs between the ages of 30 and 60, and individuals with a family history of FAD have a 50 percent chance of developing dementia. Mutations in three genes have been identified in families with early-onset AD: presenilin-1 (PSEN1), presenilin-2 (PSEN2) and amyloid precursor protein (APP). Common variations in another gene, apolipoprotein E (APOE), confer a major risk to Alzheimer’s disease in populations worldwide, but APOE risk variants are not sufficient to cause the disease.
In addition to the Center for Medical Genetics, our Center for Brain Health provides APOE genotyping as part of a comprehensive evaluation of Alzheimer’s risk and offers multidisciplinary interventions to protect against Alzheimer’s in at-risk subjects.
Huntington’s Disease (HD)
This disorder causes involuntary movements and impaired motor skills, personality and psychiatric changes, and cognitive impairment. Individuals at-risk of developing HD typically undergo genetic counseling, psychological counseling and a neurological exam before genetic testing becomes an option.
Parkinson’s Disease (PD)
PD is characterized by slowness of movement, tremors, rigidity and gait instability resulting from a depletion of a neurotransmitter called dopamine. The genetics of PD is not as straightforward as some other conditions and numerous genes have been implicated. There is genetic testing available for some rare forms of PD, but most genetic testing is still in the research phase.
Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL)
CADASIL is a neurological condition characterized by a personal and/or family history of migraines, stroke-like episodes before the age of 60, cognitive and behavioral disturbances, and dementia. The gene involved in CADASIL is called NOTCH3. Approximately 90 percent of individuals with CADASIL will have an identifiable genetic alteration in the NOTCH3 gene and genetic testing is available for individuals with a personal and/or family history of CADASIL.