Posts Tagged ‘symptoms’

Alzheimer’s Disease

May 11, 2010

Alzheimer’s disease is the most common form of dementia. Common symptoms include memory loss, confusion, irritability and aggression, mood swings and language breakdown. It is often misdiagnosed as senility. Progression of the disease varies widely. About 26.6 million people were diagnosed with Alzheimer’s in 2006.

There are two types of Alzheimer’s. Late-onset, or sporadic, Alzheimer’s is more common and is diagnosed in people 65 years of age or older. Early-onset, or familial Alzheimer’s disease (FAD), usually develops in adults in their 30’s and 40’s. This type only occurs in about 1 out of every 1000 Alzheimer’s cases. These individuals have a family history of FAD. Genetics has been linked to Alzheimer’s.

Genetics of Alzheimer’s

Genetics and Alzheimer’s are linked but the relationship is not completely understood. If a parent has been diagnosed with FAD, 50% of his offspring will develop it. It is due to autosomal dominant mutations. Therefore, even if a person has only one copy of the gene, he will develop that type. A person who has not developed the disease can not pass it on. Late-onset Alzheimer’s, on the other hand, is not inherited. There are, however, families in which clusters of cases exist.

Three genes have been discovered that influence a person’s risk of getting FAD. These include an amyloid precursor protein (APP) gene and two presenilin genes (PSEN-1 and PSEN-2). These genes exist on chromosomes 1, 14 and 21. A mutation on chromosome 21 causes a build-up in the amount of amyloid protein in the brain. An increase in the amount of amyloid protein has been linked to FAD. Mutations in all of these genes cause senile plaques.

Many genes affect a person’s chances of getting late-onset Alzheimer’s. Some genes are thought to have protective influence. A combination of multiple genes increases the risk of developing it. Only one gene has been identified so far. Apolipoprotein E (APOE) mutations are the cause of about 50% of all late-onset Alzheimer’s. It is found in three forms:

  • APOE2 gives a person some protection against getting Alzheimer’s.
  • APOE3 gives an individual an “average risk” of developing Alzheimer’s.
  • APOE4 increases a person’s risk of getting Alzheimer’s. People with one copy are four times more likely and those with two copies are ten times more likely to develop the disease. Having two copies, however, does not mean that a person will definitely get the disease.

Recent research has, however, made it possible to determine which genes have an influence on developing this disorder. It will only take time to identify these genes. The role of each gene will then be determined. It may then be possible to treat and prevent the disease.

Treatment of Alzheimer’s

Treatment is targeted at alleviating the symptoms of Alzheimer’s. Research has not yet discovered a way to prevent or delay the onset or progression of this condition. Clinical trials are ongoing. Some lifestyle changes that may help include exercise, mental stimulation and a healthy diet. Cardiovascular health and pharmaceutical products may also have an influence on one’s risk.

HIV / AIDS: Biology, Statistics, Risk Factors, Symptoms, Genetics, Tests

May 11, 2010


Human immunodeficiency virus (HIV) is a retrovirus that can result in acquired immunodeficiency syndrome (AIDS). Nine out of ten untreated individuals with HIV will develop AIDS in 10-15 years or sooner after acquiring the disease. With anti-retroviral treatment, patients have an increased life expectancy. Without treatment, patients usually die within a year.

AIDS is now considered to be pandemic. Between 1981 and 2006 it is estimated that 25 million people died from AIDS. In 2007 worldwide statistics show the following statistics:

  • 330,000 children died from AIDS
  • 2.1 million people died from AIDS
  • 33.2 million people lived with AIDS.

Over 75% of those deaths originated in sub-Saharan Africa.

The immunodeficiency affects every organ of the body. Certain conditions are more likely in a person with HIV including:

  • bacterial infections
  • cervical cancer
  • fungal infections
  • gastrointestinal infections
  • lymphomas
  • parasitic infections
  • pulmonary infections
  • tumors and malignancies
  • viral infections.

Symptoms develop from the body’s lack of having a regularly functioning immune system. Symptoms include:

  • chills
  • fever
  • sweats
  • swollen glands
  • weakness
  • weight loss.

Research has now determined that some individuals have HIV genetic resistance. Other people are more susceptible to HIV/AIDS. The risk factors that increase one’s chance of getting HIV include:

  • anal sex
  • blood exposure
  • blood transfusion recipients between 1978 and 1985
  • intravenous drug users who share syringes and/or needles
  • mother-infant transmission
  • needle stick injury
  • oral sex
  • people who have had multiple sex partners
  • people who have had sex with a man who has had sex with another man
  • sexually transmitted diseases (STD)
  • unprotected sex.

The Biology of HIV/AIDS

The human immunodeficiency virus attacks all the organs of the immune system. These include the CD4+ T cells. AIDS leads to failure of the entire immune system because CD4+ cells normally protect the body from infections. Without them opportunistic infections attack the body and can cause death.

HIV is spread from individual to individual by transfer of body fluids. This occurs by having unprotected sexual intercourse, by sharing needles or from mother to child. Infected fluids include:

  • blood
  • breast milk
  • pre-ejaculate
  • semen
  • vaginal fluid.

The Genetics of HIV/AIDS

HIV resistance is an inherited trait in about 1% of the white population, but it is rare in the African and Asian populations. This genetic disease resistance was first discovered when doctors realized that a small percentage of individuals who screened positive for HIV did not get AIDS. Chemokine coreceptors (CCR) were found to be responsible for suppressing infection. Researchers later found that people with a defective CCR5 gene are more resistant to HIV-1.

AIDS and genetic resistance research had determined that a deletion of a portion of the CC-CKR-5 gene makes the gene inaccessible to the virus. Some populations have a higher percentage of individuals with this mutation. This means that this mutation has a more recent origin.

Interpreting Your Genetic Test Results

DNA test results will determine if an individual is susceptible to HIV/AIDS or not. If one has the mutation in the gene that makes one resistant, it can be passed on to children. Those who are homozygous, or have two genes that are defective, are extremely resistant to the disease. Even though some people have a resistance to HIV, this virus has a very short replication cycle and can mutate within a short period of time. This means that even if an individual has a mutation in this gene, it does not mean that they will not get the disease.

If an individual’s genetic test results determine that they lack the “resistance” gene, this does not make the individual more susceptible to the disease than the general population. It just means that they must be careful and make the correct lifestyle choices.

 Frequently Asked Questions about HIV/AIDS Resistance

  • How safe is the blood supply in the United States?

The blood supply is the safest in the entire world. HIV testing began in 1985. All blood that was donated after this time has been HIV free. Additional testing has been added since this time. When blood has been identified as being infected, it is discarded.

  • Why is it so difficult to suppress AIDS?

The AIDS virus mutates at such a rapid rate that it is difficult to keep up with it. The best treatment at the time may be able to suppress most of the virus, but since it replicates so rapidly, at least some of the virus has become immune to the treatment.

  • Why do treatments sometimes fail?

Powerful combinations of cocktails exist to attempt to suppress AIDS. One of the reasons these treatments fail to work is the noncompliance of the patient to taking the drugs. Side effects may be unpleasant, dietary restrictions may be difficult and the act of taking dozens of pills may be daunting. If a patient does not take a dose, it could allow drug-resistant mutants to replicate and take the system over.

Recent News on HIV/AIDS Resistance

More recent research has determined that two separate genes, KIR3DL1 and HLA-B*57, are involved in resistance to AIDS. If an individual inherits a version of these genes, they might be more resistant to getting AIDS. The mechanism has not yet been explained, but this is good news.

Cystic Fibrosis: Signs and Symptoms, Causes, Treatment

May 11, 2010

Cystic fibrosis (CF) is a genetic disease affecting the mucus glands of the lungs, pancreas, liver, sinuses, intestines and sex organs. Mucus, which is normally thin and watery, usually keeps tissues moist. Those who develop CF, however, have very thick mucus which results in frequent lung infections. This mucus can block ducts leading to the pancreas as well. Sweat glands are also affected.

Signs and Symptoms of Cystic Fibrosis

Genetic tests can identify individuals with a mutated gene even before they are born. Newborn genetic screening tests can detect the disease as well. Sweat tests must be performed after birth, however, to determine if the individual is a carrier or has the disease. 

Symptoms and severity differ from person to person. One individual may have terrible lung and digestive disorders. Others may not have any symptoms until later in life. Some symptoms include:

  • bloated feeling
  • deficiency in the fat-soluble vitamins A, D, E and K
  • greasy and/or bulky stools
  • intestinal gas
  • malnourished
  • poor growth
  • shortness of breath
  • stomach pain or discomfort.

In advanced cases lung and pancreatic disorders cause many problems. Mucus in the lungs harbors bacteria which cause lung infections and blocks airways making it difficult to breathe. Respiratory failure is a major problem.

Ducts in the pancreas are blocked by mucus as well. The pancreas normally produces digestive enzymes that break down food in the intestines. If the ducts are blocked, proteins and fats will not be metabolized correctly. When this happens, the person suffers from stomach and intestinal disquietude, malnutrition and abnormal stools.

People who have CF have sweat which is five times as salty as a healthy individual’s sweat. Their mineral balance can be upset if they perspire and lose large quantities of sodium, which is very important in the body’s normal functions. This loss can also result in a heat emergency or abnormal heart rhythms.

What Causes Cystic Fibrosis

Medical research has established a genetic link to cystic fibrosis. A single gene on chromosome 7 makes a protein called the cystic fibrosis transmembrane conductance regulator (CFTR). This gene is responsible for making sweat, mucus and digestive juices. This protein controls chloride ions going in and out of cells.

People who have cystic fibrosis have a mutation in the CFTR gene. This means that chloride ions are not capable of getting through the membrane of the cells. In most cases, however, the CFTR protein is missing. The shortened version is identified by the body and destroyed.

CF is inherited and is not contagious. It is a recessive disorder, meaning people with one normal gene and one mutated gene are carriers of the disease. Offspring must inherit the mutated gene from each parent to have symptoms. Offspring of two parents who are carriers have a 25% chance of developing the disease.

Treatment for Cystic Fibrosis

Treatment involves the use of antibiotics and clearing the mucus out of the lungs. They are prescribed enzymes to help them digest their food and obtain nutrients. Surgery is sometimes necessary to clear obstructions. Lung transplants may be required if tissue damage is too severe.

Progress toward a Cure

There is no cure for CF. Cystic fibrosis prognosis is not good. But research gives hope that there is an increasing life expectancy of people with CF. Recent developments in treating and curing the disease are under development. Gene therapy is in the future. This involves placing a normal CFTR gene in the infected cells.

Some other developments toward a cure target the metabolic pathways involved in the disease. These include:

  • Correcting the problems with the lining of the lungs to prevent infections
  • Improving the mucus so it is not so thick
  • New antibiotics
  • New medications to reduce the toxic effects of the inflammatory immune response.

Breast Cancer: Symptoms, Causes, Genetics and Genetic Testing

May 11, 2010

Breast cancer is defined as cancer that originates in the breast cells. Women are 100 times more likely to develop it than men. It is the second most common form of cancer after lung cancer. Every year about 200,000 American women are diagnosed with breast cancer. It killed half a million people in 2005.

Breast cancer can spread through the lymphatic system or blood vessels to other parts of the body. This spread is referred to as metastasizing. It can metastasize to the lungs, brain, liver or bones.

There are non-specific and specific symptoms. Non-specific means that they could be symptoms for some other condition. Some non-specific symptoms include:

  • bone and joint pain
  • chills
  • discharge from one nipple
  • fever
  • jaundice.

Some specific symptoms include change in the size or shape of the breast or nipple and a lump in the breast or the lymph nodes in the armpit and/or collarbone

Inflammatory breast cancer occurs when breast cancer cells enter the small lymph vessels next to the skin. Symptoms include:

  • orange peel texture of the skin
  • pain
  • redness
  • swelling
  • warmth.

Paget’s disease of the breast also manifests itself in the skin and resembles eczema. Symptoms may include:

  • discharge
  • itching
  • lump
  • mild flaking of the skin around the nipple
  • redness
  • sensitivity
  • tingling.

Causes of Breast Cancer

Breast cancer stems from a combination of hereditary and environmental influences. People who have a family history with multiple cases of breast or ovarian cancer are at higher risk of getting breast cancer. Breast cancer is more common if one has an Ashkenazi (Eastern European) Jewish background. It usually occurs sporadically and is not inherited. Some risk factors include:

  • age
  • alcohol intake
  • childbearing
  • environmental factors like radiation and tobacco use
  • high fat intake
  • hormones
  • obesity
  • sex.

Genetics of Breast Cancer

About 5-10% of those diagnosed have a hereditary form of breast cancer. If a person inherits a mutation in the breast cancer 1 (BRCA1) or breast cancer 2 (BRCA2) genes, she is at higher risk of developing breast cancer. It is rare to inherit a mutation. Only one in 1000 has a mutation in one of these genes.

People who have the mutation may get cancer or may lead a long healthy life. Having a mutation does not guarantee the individual will develop cancer. About 13% of the population develops breast cancer. Those with a mutation in either of these genes are three to seven times more likely to get it.

How Genetic Testing Is Done for Breast Cancer Patients

Genetic testing looks at sequences of DNA to identify changes. The sequence of DNA has been determined for healthy people. If there is a mutation in a gene, it can make a person more susceptible to certain diseases. Certain inherited conditions have been linked to mutations in certain genes. Genetic testing is the comparison of the sequence of sample DNA to the agreed upon sequence for a normal gene to identify these risks.

Genetic testing for breast cancer is only performed on people who are at high risk of getting cancer. This blood test identifies the presence of mutations in the BRCA genes. A breast cancer genetic testing lab determines the patient’s risk of getting cancer. Genetic counseling is included in this test to make sure people are informed of their risk and options for the future.

Progress toward a Cure

Treatment for breast cancer today relies heavily on surgery, chemotherapy and radiation. Gene therapy is one option of curing breast cancer. It is not yet possible, but eventually doctors will be able to fix the mutations in the genes. Research continues to search for more genes that influence a person’s risk of developing breast cancer.

Some ways to prevent breast cancer include:

  • Chemoprevention – Some medications, such as tamoxifen, decrease one’s chance of developing cancer.
  • Mastectomy – Preventative removal of breast tissue reduces the risk of cancer by 90%.
  • Surveillance – More frequent self-exams, clinical exams, MRI’s and mammograms discover cancer earlier.