Alzheimer's disease: age of onset, genetic factors, and inheritance patterns

Alzheimer's Disease And Aging

At what age do people start to get Alzheimer's?

Alzheimer disease (AD) usually does not start until around 65 years of age or older. It is characterized by gradually worsening dementia (forgetfulness) caused by cerebral atrophy (deterioration). It is the most common form of dementia. Fewer than 2% of families with AD have early-onset familial AD (EOFAD), in which symptoms occur before the age of 65 years. EOFAD only refers to families in which multiple cases of AD occur. Early onset may happen in the 40s or early 50s, although early onset in the 30s has been reported. Sixty-one percent of individuals with early-onset AD had a positive family history and thirteen percent affected individuals in three generations. EOFAD is not any different from non-familial AD, except it is based on family history and age of onset. (Bird, 2005)

Genetics usually cause Alzheimer disease, but there are also unknown causes. Vascular dementia, another common form of forgetfulness, results from reduced blood flow to the brain's nerve cells. In some cases, Alzheimer's disease and vascular dementia can occur together in a condition called "mixed dementia." Other causes of dementia include frontotemporal dementia, dementia with Lewy bodies, Creutzfeldt-Jakob disease and Parkinson's disease. The earlier the onset of Alzheimer's disease, frontotemporal dementia, and other non-Alzheimer dementias, the more likely it is they are inherited (Nee, 219)

Although there is currently no cure for Alzheimer's, new treatments are on the horizon as a result of increased research and discoveries about the biology of the disease. Studies have also shown that effective care and support can improve quality of life for individuals and their caregivers over the course of the disease from diagnosis to the end of life.

All of these questions (What is Alzheimer disease? What are its causes? And Can medication prevent it?) are treated in this paper.

1. Why I picked this topic:

My Grandfather had it.

2. Definition: (how it happens, what is it?)

Alzheimer's disease is a progressive brain disorder that gradually destroys a person's memory and ability to make judgments, learn, communicate, reason and carry out daily activities. As Alzheimer's progresses, individuals also experience changes in personality and behavior, such as anxiety, suspiciousness or agitation, as well as delusions or hallucinations.

Four major types of familial Alzheimer disease have been identified. Types 1, 3, and 4 are classified as early-onset Alzheimer disease because their signs and symptoms appear before age 65. Type 2 is classified as late-onset Alzheimer disease because its signs and symptoms appear after age 65 (Pollen, p. 5). The difference between AD and Early Onset Familial Alzheimer Disease (EOFAD) is becoming less obvious as more research on the disease is done.

Close relatives of an individual with AD have about a 20% lifetime risk of developing AD. Presumably, when several individuals in a family have AD, the risk is increased. EOFAD is often inherited in an "autosomal dominant manner." The risk to children of individuals with EOFAD is 50% if a www.geneclinics.org/servlet/access?qry=139&db=genestar&fcn=term&gtreport2=true&id=8888890&key=MY89iv-vDQpDO&format=framemutation is found. Other causes of dementia are treatable. These are conditions which affect memory decline, such as depression, chronic drug intoxication, chronic CNS infection, thyroid disease, vitamin deficiencies (especially B12 and thiamine), CNS angitis, and normal pressure hydrocephalus (Chan, p. 1121).

Alzheimer disease is characterized by adult-onset slowly progressive dementia associated with diffuse cerebral atrophy on neuroimaging studies. It is the most common form of dementia." (Bird, 2005).

3. Causes

The exact cause of the disease is unknown. A common view among doctors is that non-familial AD has many factors that cause it and that it results from a combination of aging, www.geneclinics.org/servlet/access?qry=72&db=genestar&fcn=term&gtreport2=true&id=8888890&key=MY89iv-vDQpDO&format=framegenetic tendencies, and possibly one or more environmental events, such as head trauma, viruses or contaminants, although no environmental agents have been proven to be directly involved in the cause of AD. Molecular genetics have been studied to find at least three subtypes of EOFAD based on the causative www.geneclinics.org/servlet/access?qry=66&db=genestar&fcn=term&gtreport2=true&id=8888890&key=MY89iv-vDQpDO&format=framegene. It is likely that other www.geneclinics.org/servlet/access?qry=66&db=genestar&fcn=term&gtreport2=true&id=8888890&key=MY89iv-vDQpDO&format=framegenes will be identified as a cause of EOFAD because people www.geneclinics.org/servlet/access?qry=112&db=genestar&fcn=term&gtreport2=true&id=8888890&key=MY89iv-vDQpDO&format=framekin to those having the disease, with no known www.geneclinics.org/servlet/access?qry=139&db=genestar&fcn=term&gtreport2=true&id=8888890&key=MY89iv-vDQpDO&format=framemutations in PSEN1, PSEN2, or APP, have been found. (Tanzi, p. 35)

Health Issues

Symptoms of early-onset Alzheimer's disease are similar to those of late-onset Alzheimer's disease, except that the younger person often is still active with work, family and social activities when the symptoms begin. Younger people who develop Alzheimer's disease tend to have more of the negative changes found in the brains of those with late-onset Alzheimer's disease. These changes include twisted nerve cell fibers, known as neurofibrillary tangles, and a sticky protein called beta amyloid, which forms structures called plaques. Plaques and nerve twists damage healthy brain cells that surround them, causing cells in the brain to wither and die. Some believe that younger brains need to suffer more damage than older brains before the patient begins to show symptoms, so the nature of the disease may not be that much different (Chan, p. 1121).

Symptoms

The main symptom of Alzheimer disease (AD) is dementia that typically begins with subtle and a not very well recognized failure of memory which slowly becomes more severe and, eventually, incapacitating. Other common symptoms include confusion, poor judgment, language disturbance, agitation, withdrawal, and hallucinations. Occasionally there are seizures, Parkinson's disease-like features, increased muscle tone. Myoclonus, incontinence, and mutism sometime occur. "Death usually results from general inanition, malnutrition, and pneumonia. Death usually results from pneumonia, malnutrition, or general body wasting. The duration of the disease is eight to ten years, with outside ranges of one to 25 years. (Tanzi, p. 59)

Early Warning Signs

Memory loss is the most common sign of Alzheimer disease. Memory worsens over time and interferes with most aspects of daily living. A person with Alzheimer disease may get lost or become confused even at home. The patient is challenged to do even routine tasks such as preparing meals, doing laundry, and performing other household chores. It may become difficult for the patient to recognize people and name objects. They may gradually require more help with dressing, eating, and personal care.

Hereditary

About 75% of Alzheimer disease cases are classified as sporadic, which means that, even with no history of the disorder in a family, they happen. While the cause is unknown, gene changes may play a role. Virtually all sporadic Alzheimer disease begins after age 65. The remaining cases of Alzheimer disease are found in multiple members of a family. Hereditary Alzheimer disease can be divided into early-onset disease (symptoms beginning before age 65) and late-onset disease (symptoms beginning after age 65) (Chan, p. 1121).

The Stages of Alzheimer disease

As the disease progresses, some with Alzheimer disease experience personality and behavioral changes and have difficulty in social setting. Other symptoms include irritability, restlessness, withdrawal, and problems with speaking. The advanced stage usually requires comprehensive care. After the symptoms first appear, affected individuals usually survive 8 to 10 years, but the disease can last from 1 to 25 years. "Death usually results from general inanition, malnutrition, and pneumonia." (Bird, 2005).

Drugs for Alzheimer Disease

Medication can improve the quality of life for people with Alzheimer's and their caregivers. It may even delay placement in a nursing home.

A. Names of Drugs

The U.S. Food and Drug Administration (FDA) has approved two classes of drugs to treat cognitive symptoms of Alzheimer's disease. The first Alzheimer medications approved were cholinesterase inhibitors. About half of the people who take these experience a little improvement in brain-related symptoms.

Three of these drugs are commonly prescribed:

Donepezil (Aricept®), approved for all stages of Alzheimer's disease

Rivastigmine (Exelon®), approved for mild to moderate Alzheimer's disease

And galantamine (approved in 2001 under the trade name Reminyl® and renamed Razadyne® in 2005), also approved for mild to moderate stages (Genetics, 2006)

Treatment trials evaluating use of anti-inflammatory agents (NSAIDs), estrogens, nerve growth factors, and antioxidants are underway. Vitamins and other over-the-counter medications have been used in the treatment of AD. Some, but not all, reports suggest that www.geneclinics.org/servlet/access?qry=252&db=genestar&fcn=term&gtreport2=true&id=8888890&key=MY89iv-vDQpDO&format=frameaffected individuals taking HMG-coenzyme A reductase inhibitors for hypercholesteralemia have a reduced incidence of dementia. Immunization of an AD mouse model has stimulated the search for a possible vaccination approach to the treatment of human AD. A human trial of this approach was halted because of encephalitis in a few subjects (Genetics, 2006).

Memantine (Namenda®) is a drug approved in October 2003 by the FDA for treatment of moderate to severe Alzheimer's disease. Memantine may protect cells against excess glutamate by partially blocking NMDA receptors (Genetics, 2006).

B. Side Effects of Pills

Tacrine (Cognex®), the first cholinesterase inhibitor, was approved in 1993 but is rarely prescribed today because of associated side effects, including possible liver damage.

Research has shown that taking vitamin E supplements may offer some benefit to people with Alzheimer disease, but A person taking "blood-thinners," may not be able to take Vitamin E or will need to be monitored closely by a physician.

Alternative Treatment

Frustration with the progression of symptoms of Alzheimer disease may cause some people to try alternative medicines. Some treatments may actually help with the disease.

5. Medication

The AD patient should talk with the family and doctor about what medical treatments they want to receive in the event they become unable to communicate their wishes. The AD patient may also wish to prepare an advance directive, a legal document that outlines wishes for future medical treatment, as well as a living will.

Behaviors

Exercise is emerging as a possible help in preventing or delaying Alzheimer's. It has long been known that lifelong exercise reduces a person's risk of developing high blood pressure, stroke, and cardiovascular diseases, which in turn decrease the risk of Alzheimer's. The brain benefits greatly from the increased blood circulation brought about and sustained by regular physical activity. Exercise is also an excellent way to release stress and improve overall physical and emotional health (Genetics, 2006).

A key principle of intervention is redirecting the affected individual's attention, rather than arguing, disagreeing, or being confrontational with the person. Additional intervention strategies include the following: simplify the environment, simplify tasks and routines and use lighting to reduce confusion and restlessness at night.

Alternative Living Choices

Living at Home

Alzheimer's disease affects each person differently. The patient will have good days and bad days. A family with an AD patient must try to maximize the good days and not dwell on the bad days, remembering that they are not alone. They should consider joining a support group, by calling a local chapter of the Alzheimer's Association for information on support groups for people with Alzheimer's disease. Neither family members nor the AD patient should keep fears and feelings inside or remain without counsel. The patient and family should seek professional counseling, and share feelings with friends, family or a clergy members.

Family's responsibility

The Genetic and Rare Diseases Information Center was established by the National Human Genome Research Institute (NHGRI) and the Office of Rare Diseases (ORD). It employs experienced information specialists to answer questions from the general public, including patients and their families, about care of patients living at home or in nursing homes. There are also resources for finding information on financial aid for medical treatment available from Genetic and Rare Diseases Resources. This group also offers reliable health information to families of AD patients (Bird, 2005).

Home Safety

Taking care of the patient with AD is a large responsibility. The patient should get regular check-ups, and follow doctor's recommendations about diet, exercise and taking medications. They should also be watched so that they will not wander away from the house they live in, for they may forget how to return, they also need adequate rest between stimulating events, labels to cue or remind them of activities and times, doors and gates with safety locks, and guns should be removed from the house.

Caregivers' roles

Caregivers need to feed, bathe, change clothing, help with personal care and do daily chores for the person they are caring for. Taking care of an Alzheimer's patient may be too much for one person to handle at times; it is certainly beneficial to get some relief from care responsibilities. The local Area Agency on Aging (AAA) Eldercare Locator can connect a caregiver to helpful services in the area, including ride programs, home health services, and companion/respite care options.

Adult Daycare

Alzheimer disease patients are usually elderly people who need care during their waking hours. Often a family or spouse cannot fulfill this responsibility completely because of its demands or because they have other jobs. That is when adult daycare can help.

Assisted Living

Assisted Living is also called board and care, adult daycare, adult living, or supported care. It bridges the gap between living independently and living in a care facility or nursing home. Assisted living typically offers a combination of housing and meals, and supportive and health care services either at home or in a facility where the patient spends the day. The federal government does not regulate assisted living, and definitions of assisted living vary from state to state, so the search for an agency or person to help with assisted living should be done with much careful research beforehand.

Nursing homes

Nursing homes, also called skilled nursing facilities, long-term care facilities, or custodial care, provide long-term care to individuals who require constant nursing care and supervision. Most nursing homes have specialized services and staff to treat nutrition, care planning, recreation, spirituality and medical care. Nursing homes are usually licensed by the state and regulated by the federal government. Traditionally, nursing homes cared only for those who could no longer care for themselves and whose families could no longer provide adequate care. Now they include a variety of possible living arrangements.

Levels of nursing homes

Today, the trend of care facilities is toward "life care" or "stepped care" facilities. These complexes typically offer three levels of care: independent apartments for people who can still take good care for themselves; assisted living facilities for those who need help with meals, laundry, medications, etc.; and a nursing home for those who need greater supervision and care. Once a patient comes to live in the facility, they can move from one level to another level of care according to their need. Alzheimer special care units (SCUs) are special units designed to meet the unique needs of individuals with Alzheimer's disease and other dementias. SCUs may take various forms and exist within different types of residential care. These units are cluster settings where patients with dementia are put together on a floor or unit within a larger residential care facility.

Sleep disorders

Older people are thought of as light sleepers. Although the amount of sleep each person needs varies widely, the average is between seven and eight hours a night. As people age, the amount of sleep one can expect to get at any one time drops off. Insomnia is the most common sleep complaint among aging people, including those with Alzheimer disease. Insomnia's symptoms include taking a long time to fall asleep (more than 30 to 45 minutes), waking up many times each night, waking up early and being unable to go back to sleep, and waking up feeling tired. There are organizations that may help with this disorder in an AD patient. The Better Sleep Council, the National Center for Sleep Disorders Research and the National Sleep Foundation are just three of them.

Planning an outing

Research suggests that exercise might actually shift the body's (and brain's) metabolic pathways toward the healthy processes that break down the amyloid precursor protein and prevent the buildup of deposits. Outings are good for the AD patient. The caregiver needs to choose how the transportation will be arranged and how it will affect the AD patient. The plan for the destination to be safe and enjoyable is important, as well as accepting of a patient that may be irritable and forgetful.

Financial, insurance and legal issues

Families must plan ahead for financial needs, knowing that eventually the AD patient will have to leave their job and will lose their income. It is also best to meet with a financial counselor who can help the AD patient investigate insurance, investments and other financial options. Organizing all of the AD patient's financial and legal documents, as well as other important information (insurance policies, Social Security information, wills, etc.) in one place, will help everyone know where to find them when necessary.

Living with Alzheimer disease

Alzheimer's disease advances at widely different rates. The duration of the illness may often vary from 1 to 25 years. Diseased patients' families will have to accept many changes.

Lifestyle changes

The condition of the individual with Alzheimer disease will eventually be complete deterioration, but within a few years, the individual with Alzheimer disease will need 24-hour care (Imperial, 1998). This is a large lifestyle change for the patient and the patient's family.

Support organizations and coping

There are four major support organizations for patients and families of those with AD, the Alzheimer's Association, the Alzheimer's Foundation of America, the Alzheimer Research Forum and the National Organization for Rare Disorders (Pollen, p. 196).

Future issues

Eventually, genetic counseling may find out if future babies in a family with AD have the gene that determines that they will get AD. When several individuals in a family have AD, the risk is increased. It is best to be tested if someone in the family has had AD. Another future development is a preimplantation genetic diagnosis to avoid the conception of a child that could have inherited a predisposition to early-onset Alzheimer disease. (Bird, 2005)

What did I learn about Alzheimer's?

A learned about what Alzheimer disease really is, its symptoms and causes. I learned that Alzheimer disease is often inherited, but that it can be delayed or arrested by diet, activity and medications. I also learned about caring for a person with Alzheimer disease and that there are many organizations and facilities dedicated to helping those with needs related to Alzheimer disease.