Saturday, September 11, 2010

Genetically Transmitted Diseases/Disorders

A genetic disease can be the result of mutation in a gene. According to ThinkQuest.org online library there are currently more than 4,000 known genetically transmitted diseases with more being discovered every year. Genetic diseases can be inherited from parents by children. Some genetic diseases are extremely rare, while some genetic diseases are more widespread. 


People who are curious as to their chances of inheriting or passing on a genetic disease can get genetic testing.

Cystic Fibrosis

  • Cystic fibrosis affects more than 30,000 children and adults in the United States today, according to the Cystic Fibrosis Foundation. It is also life-threatening as it causes mucus to build up and clog organs in the body. Mucus and bacteria build up in airways and cause severe swelling that can lead to lung damage.

    According to the Cystic Fibrosis Foundation in order to inherit the disease one must inherit two copies of the defective cystic fibrosis gene. This means the individual must inherit a copy of the defective gene from both parents.

  • Chronic Granulomatous Diseases

  • Chronic granulomatous diseases are genetically transmitted diseases in which the immune system is affected and compromised. The immune system cells are not able to efficiently form compounds that are necessary to kill pathogens. This inefficiency leads to granulomas which are ineffective at fighting disease and infection. A granuloma is essentially a small tumor or small area of inflammation. Usually the inflammation is caused from a tissue injury or infection, however in patients with CGD the granulomas are chronic.

    According to a study in 2004 conducted by Dr. Maryland Pao, et al., chronic granulomatous diseases affect one in 200,000 people, and there were an average of 20 new cases each year.

    Symptoms of CGD can include but are not limited to superficial skin infections, abscesses of the skin tissues and organs, arthritis and pneumonia.

  • Mucopolysaccaridosis Diseases

  • Mucopolysaccaridosis diseases are genetically transmitted diseases that affect the functions and abilities of the enzymes to break down sugars. The inability to break down the sugars leads to a build up in the cells and the blood which leads to permanent cellular damage.

  • Phenlketonuria

  • Phenlketonuria is a genetically transmitted disease in which the body's ability to metabolize phenylalanine is compromised. When left untreated this genetically transmitted disease can lead to brain damage as well as mental retardation.

    When discovered early enough in childhood a special diet can be maintained, and the child can grow with normal brain development. A special diet includes limited amounts of breast milk, cheese and other dairy products as well as limited amounts of meat and chicken, nuts and fish.

  • Turner's Syndrome

  • Turner's syndrome is a series of genetically transmitted diseases that affect the chromosomes. There are many different types of syndromes depending upon the chromosomal makeup the individual has inherited. Symptoms of Turner's syndrome can include swelling of the hands and feet, a short stature and broad chest, a low hairline and low set ears, and being reproductively sterile.

    It is common for a fetus with Turner's Syndrome to spontaneously abort.

  • Celiac Disease

  • According to the Celiac Spruce Association, one in 133 people are affected by celiac disease. The disease can lay dormant until triggered by gluten in food. It is not uncommon for gluten in food to set off a response in a person's body which causes damage to the small intestine which leads to the small intestine being unable to absorb nutrients in food and causing malnutrition.

    Contrary to popular belief, celiac disease is not a food allergy and is not age-dependent. Celiac disease can appear or become active at any age

  • Jewish genetically transmitted diseases

    That only effect the Jewish people? The list is near endless but here’s a small sample of ailments, quite a few are exclusive to their people. Chosen for disease one might say? If there are any explanations or theories behind this I would like to know.
    Alpha 1-anti-trypsin Deficiency
    Amyotrophic Lateral Sclerosis
    Aut. Dom. Optic Atrophy
    Aut. Dom. Retinitis pigmentosa
    Bardet Biedl syndrome
    Berger’s Disease
    Beta-thalassemia
    Bloom Syndrome
    Canavan disease
    Celiac Disease, or Sprue
    Color-blindness
    Con. Stat. Night Blindness
    Congenital blindness
    Congenital deafness
    Corneal Dystrophy
    Crohn’s Disease
    Cystic fibrosis
    Dwarfism
    Hereditary Hearing Loss
    Kaposi’s sarcoma
    Lactose intolerance
    Leber’s congenital amaurosis
    Lipoamide Dehydrogenase-
    Deficiency
    Early rheumatoid arthritis, often
    occurring in childhood
    Elephant man’s disease- Proteus
    syndrome
    Fabry Disease
    Factor XI deficiency
    Familial Dysautonomia
    Familial Hypercholesterolemia
    Familial hyperinsulinemia
    Familial Mediterranean fever
    Fanconi Anemia
    Gaucher Disease
    Glucose-6-phosphate-
    dehydrogenase deficiency
    Glycogen storage disease type 1a
    Glycogen storage disease type III
    Machado Joseph Disease
    Malformed limbs
    Maple syrup urine disease
    Mucolipidosis IV
    Multiple Sclerosis
    Muscular Dystrophy
    Nemaline Myopathy
    Niemann-Pick disease
    Non-Classical Adrenal Hyperplasia
    Non-syndromic sensorineural
    Progeria
    Psychotic disorders- abnormally high incidence of
    Rib cage misaligned
    Stargardt disease
    Tay Sachs
    Temperature intolerance
    Thalassemia
    Torsion Dystonia
    Type III Glycogen Storage disease
    Usher Syndrome Type 1F
    Vitelliform Macular Dystrophy
    Wilson disease

    What is genetic screening?

    What is newborn genetic screening?
    Newborn genetic screening is a health program that identifies treatable genetic disorders in newborn infants. Early intervention to treat these disorders can eliminate or reduce symptoms that might otherwise cause a lifetime of disability.
    Who performs newborn screening?
    Newborn genetic screening programs are conducted worldwide. In the United States, newborn screening programs are developed and run by individual states. Each state decides which disorders to test for and how to cover the costs of screening.
    Who is screened?
    In most cases, newborn infants are automatically screened in the hospital shortly after delivery.
    Who pays for screening?
    Individual states in the United States finance their newborn screening programs in different ways. Most states collect a fee for screening, which ranges from less than $15 to nearly $60 per newborn. Health insurance or other programs can pay this fee for the newborn's parents.
    Often, the fee charged does not fully cover the cost of screening, so public health system funding is used to supplement the program. Financing a screening program comes with an expectation that the benefits of testing - early detection and treatment - will equal or exceed the cost.
    Who decides?
    Lawmakers in each state have enacted legislation that defines the state's newborn screening program. From time to time, these programs need review and revision to incorporate new technologies, address financial issues and ensure that the screening program is meeting the needs of the state's residents.
    When developing a policy, lawmakers must consider the following questions
    • Which disorders should be included in the screening program?
    • Who pays for the screening program, and how?
    • Who should be screened?
    • Who has access to test results?
    • Who benefits from the screening program?
    • What are the potential risks of screening?

    Genetic Research

    Research advances in genetics are in the news almost every day. Many of these news reports tell of the discovery of a gene that causes a disease or other medical problem. While these reports are often exciting and provocative, it is often not easy to understand exactly what has been discovered and how that discovery will help the people with that disorder. There are a number of studies on the genetics of stuttering now in progress. Findings from these studies are beginning to appear, and there is much hope that more discoveries, telling us more important information about stuttering, will soon be made. What exactly are these studies, and what do scientists hope to learn from them?
    Several of the current genetic studies on stuttering, including our NIH Family Research Project on Stuttering, are technically known as linkage studies. In linkage studies, scientists attempt to find genetic markers that are co-inherited with stuttering in families. This co-inheritance in families is known as linkage. When a marker or markers show co-inheritance with stuttering, scientists know that these markers lie very close to the gene or genes that help cause stuttering in those families. Since scientists already know the location of each marker they test, discovering linkage to a marker tells them the location of the gene(s) involved. If scientists can find the location of these genes, they can learn a great deal about the contribution of each one of those genes to stuttering. In addition, they can use the information on where the genes are located to find, isolate, and study these genes.
    What are these genetic markers? Anything that shows inherited differences in people is a genetic marker. A good example is your blood type. A personĂ¾s blood type can be type A, type B, or type O, and each person inherits their blood type from their parents. The gene which specifies blood type resides on chromosome number 9. One of the first examples of linkage ever demonstrated in humans was co-inheritance of ABO blood type with a rare and unusual disease called nail-patella syndrome, in which people have abnormal fingernails and kneecaps. Knowing that the gene causing nail-patella syndrome is linked to the ABO blood type gene told scientists that the nail-patella syndrome gene is on chromosome number 9 as well. This information on where this gene is located allowed scientists to find this gene and to see how it was different in people with nail-patella syndrome. This discovery revealed new information on how fingernails and kneecaps develop, and how these two parts of the body are actually related to each other. The goal of linkage studies on stuttering are exactly the same.
    Scientists hope to find the genes that can cause stuttering, to see what these genes do, both in normally fluent people and in those who stutter. How will this help people who stutter? First, despite decades of effort by dedicated researchers, no underlying cause of stuttering has been found. While many stuttering therapy methods have proven to be helpful, understanding the underlying causes of stuttering will be a tremendous aid in designing new and better therapies. Even before this point, however, having good genetic markers for stuttering could help with stuttering diagnosis, identifying those that stutter because of genetic factors. These could help identify individuals at risk in families, and help get early intervention started in those who need it most. It's an exciting time in stuttering research. We have good reason to hope for better understanding of

    chromosomal disorders|chromosomal diseases


    Most human cells contain 46 chromosomes, or 23 pairs of homologous chromosomes. Each chromosome of the pair is the same shape and size and has the same genes in the same location. Chromosome disorders occur due to two types of alteration in the chromosomes. Chromosome disorders can be caused by an alteration in the number of chromosomes in the nucleus, or by an alteration in the structure of a chromosome.

    Syndrome caused by chromosome abnormality. Normally, humans have 23 pairs of chromosomes, including one pair of sex chromosomes. Any variation from this pattern causes abnormalities. A chromosome may be duplicated  or absent; one or more extra full sets of chromosomes can be present (see ploidy); or part of a chromosome may be missing (deletion) or transferred to another (translocation). Resulting disorders include Down syndrome, intellectual disability, heart malformation, abnormal sexual development, malignancies, and sex-chromosome disorders (e.g., Turner syndrome, Klinefelter syndrome). Chromosomal disorders occur in 0.5% of births; many can now be diagnosed before birth by amniocentesis.

    Sex cells, or gametes, have only 23 chromosomes. When the sex cells are produced, chromosomes separate and move to opposite ends of the cell. Sometimes a chromosome moves to the same end of the cell as its pair, instead of the opposite end. This extra chromosome is incorporated into the nucleus of the daughter cell, causing it to have an extra chromosome, a nondisjunction. As a result, one of the gamete cells will have two copies of the chromosome and the other will have none.

    During fertilization, a sperm cell merges with an egg cell producing a zygote with two copies of each chromosome. If a nondisjunction has occurred, and a gamete with the wrong number of chromosomes unites with another, the resulting cell will have the wrong number of chromosomes. If the cell has too many chromosomes, it is said to be polyploidy. Often, the cell only has one extra copy of a chromosome, or three in humans, so it is called a trisomic cell. If the cell only has one copy of a chromosome, it is called a monosomic cell.

    Nondisjunctions in human cells are relatively high. The results are often lethal to the developing fetus though, so it usually doesn't survive. Chromosome disorders caused by nondisjunctions that do result in children being born are:

        * Down syndrome – An extra chromosome 21 is present so it is also called trisomy 21. The affects range from moderate to severe and those with Down syndrome have characteristic facial features, a short stature and heart defects. They often suffer from respiratory diseases, have a shorter life span and some degree of mental retardation.

        * Patau syndrome – This syndrome results from a trisomy of chromosome 13. It causes severe eye, brain and circulatory defects. Cleft palate is often a result and the children rarely live longer than a few months.

        * Edward’s syndrome – Children with Edward’s syndrome rarely live longer than a few months, as all of their organs are affected in some way. This condition is caused by trisomy 18.

        * Klinefelter’s syndrome – Individuals with this syndrome have multiple copies of the X chromosome, XXY, XXXY or XXXXY. These individuals are male, but the presence of extra X chromosomes causes body proportions that are female and smaller testes with no sperm development. The greater the number of X chromosomes, the more marked the condition.

        * Turner’s syndrome – Children with Turner’s syndrome have only one X chromosome, so they have only 45 chromosomes in total. This is the only non-lethal monosomy in humans, but most do not survive the pregnancy. Those that are born are female, but they are small in stature and do not mature sexually.

    Changes in structure are what cause the other chromosome disorders. There are four changes that can occur in chromosome structure to cause chromosome disorders – deletions, inversions, translocations and duplications. These structural changes are due to chromosomes breaking and then not reattaching correctly.

    During a deletion, a part of the chromosome is lost. As a result, this can cause a loss of the genes on that portion of the chromosome. Losing genes can significantly affect an organism’s development and can often prove lethal. Cri du chat is a chromosome disorder caused by the deletion of part of chromosome 5. It results in severe mental retardation, a very small head with unusual features and the child makes a distinct cry that sounds like an upset cat.

    During an inversion, a portion of the chromosome is reattached in the inverted position, causing the sequence of the genes on this portion to be reversed. While the overall genetic information is the same, the characteristics affected by the genes may be changed. If a portion of a chromosome is reattached at a different point on the same chromosome, or to a new chromosome, a translocation has occurred. Like an inversion, this can also cause changes in the characteristics of the individual depending on how, where and what was moved.

    Tay-Sachs Disease

    Tay-Sachs Disease is one of the most lethal genetic disorders The causes of Tay Sachs disease lie in a mutation in a single gene (monogenic genetic disease). The mutation that is responsible for the disease lies in the gene Hex A. This gene codes for the enzyme hexaminidase A and is found in the chromosome 15. The normal protein catalyzes the degradation of some fatty acids called gangliosides. Tay-Sachs Disease is a devastating and fatal illness caused by the lack of the enzyme hexosaminidase A (hex A). Tay-Sachs is of genetic origin. All who have Tay-Sachs get it from two parents who carry a recessive gene for the disease. These parents do not have Tay-Sachs because the disease in both its most common forms, infantile and juvenile Tay-Sachs result in mortality before children reach adulthoodThe most important ganglioside for Tay-Sachs is the Ganglioside GM2. This material is found in the nerve cells of the brain and especially in the cell membranes. In the case of Tay-Sachs Disease there is no enough activity of the enzyme and the gangliosides are accumulated with destructive results.
    Answering to the question whether there is only one specific mutation that leads to Tay Sachs or not, we have to say that the mutations can happen to more than one site of the gene. A large number of HEXA mutations have been discovered, and new ones are still being reported. These mutations reach significant frequencies in several populations.





    The cause of this deterioration is that hex A is not present to break down fatty tissues in the brain and nerves. Failure to metabolize these substances gradually results in the above symptoms and death, since the brain and nerves become more and more impaired by fatty tissues.

    Juvenile Tay-Sachs causes affected children to develop symptoms around the age of three, though this can vary anywhere from two to five. The progression of the disease is very slow, taking up to 12 or 13 years for death to occur. Parents are heartbroken to see their children gradually lose previously acquired functions like talking and walking. Children with juvenile Tay-Sachs may still have the ability to understand, but speech if it exists will be slurred and unintelligible in late stages. Juvenile Tay-Sachs is also associated with more pain, as frequent muscle spasms and cramps occur.

    On rare occasions, an adult will develop a hex A deficiency. His or her disease will be similar in course to those affected by juvenile Tay-Sachs. Predictors for this deficiency in adults are not well defined.

    Tay-Sachs is often associated with European Jews. They do have the highest rate of being carriers of the gene responsible for Hex A deficiency. However, not only Jewish children get Tay-Sachs. The existence of the illness has been noticed in some French Canadians. As well, those whose have Cajun ancestry are more at risk.

    One parent, who is a carrier, has a 50% chance of passing the carrying gene to children. When both parents are carriers each child has a 25% chance of being born with Tay-Sachs. Each child also will inherit a gene to carry the disease. Tay-Sachs can be diagnosed with chronic villus sampling during the early part of pregnancy. Many who then receive a positive diagnosis are faced with the difficult decision of whether to end a pregnancy and the life of their child at this point, since the outcome of the disease is likely fatal.

    Blood Diseases

    Blood is the life-maintaining fluid that circulates through the body's heart, arteries, veins, and capillaries. It carries away waste matter and carbon dioxide, and brings nourishment, electrolytes, hormones, vitamins, antibodies, heat, and oxygen to the tissues.
    Because the functions of blood are many and complex, there are many disorders that require clinical care by a physician or other healthcare professional. These conditions include benign (non-cancerous) disorders, as well as cancers that occur in blood.

    A blood disease is a disease which affects the blood. Many blood diseases are congenital, the result of inherited genetic disorders. Others may be acquired, typically in response to some sort of stress in the body. Blood diseases or blood disorders as they are sometimes called are distinct from blood-borne diseases, diseases which are carried in the blood. One of the key differences between a blood disease and a blood-borne disease is that blood diseases are not contagious
    There are four types of blood disease. Coagulopathies are disorders which concern bleeding and clotting, such as hemophilia. Anemias concern the lack of hemoglobin, a substance in red blood cells which is vitally necessary for oxygen transport. Hematological malignancies like leukemia are cancers which affect the blood and bone marrow, while hemoglobinopathies are blood diseases which have to do with the structure of red blood cells. Sickle cell anemia is a classic example of a hemoglobinopathy.

    In the case of a blood disease that is caused by genetics, the treatment for the disease is usually focused on managing the symptoms to keep the patient comfortable and help him or her lead a normal life. In hemophilia, for example, the patient is provided with clotting factors so that the blood clots normally. These diseases cannot be cured, but they can often be managed very effectively. With the use of gene therapy in the future, it may be possible to address the underlying cause of such disorders.

    Blood diseases with external causes such as disease leading to anemia can be treated by addressing the cause, which also clears up the disease. In the case of blood malignancies, the blood may be treated with chemotherapy and radiation to kill the malignant cells, with more extreme procedures like marrow transplants and blood infusions being used in particularly aggressive cases.

    Many blood diseases are identified early, because the symptoms can be very debilitating for the patient. In the case of genetic diseases, people who know that their children are at risk may request testing shortly after birth to see if the genetic disorder is present, and some parents use genetic testing in assisted reproduction to select embryos which are free of the genetic disorder. In other instances, people go to the doctor for symptoms like fatigue, pale gums, excessive bleeding or clotting, joint pain, and so forth, and the blood disease is diagnosed with the assistance of medical tests.





    Blood disease breakthroughs begin here

    Many of the most significant advances in the treatment of leukemia, lymphoma and other blood diseases began here at the Hutchinson Center. These accomplishments pave the way for the future of cancer care.

    Mini-transplants deliver big results for more patients
    We have developed a milder blood stem-cell transplant that relies on the power of donor immune cells to fight cancer and eliminates the need for painful chemotherapy and radiation. The mini-transplant typically involves no hospitalization and is extremely successful for treating older patients with blood cancers who are unable to tolerate chemotherapy and radiation. At the Hutchinson Center, we're testing the procedure's effectiveness in children as well as young women who wish to preserve their fertility.

    Harnessing the immune system to fight cancer
    Our Nobel Prize-winning work on bone-marrow transplantation revealed the remarkable cancer-fighting power of the immune system. Today, we lead a revolutionary new field called immunotherapy that yields powerful cancer treatments with far fewer side effects than conventional drugs, radiation or surgery. This innovative approach uses antibodies called T-cells that deliver chemotherapy and radiation directly to cancer cells. It also includes cutting-edge vaccines to stimulate the immune system to fight cancer relapse.

    Preventing relapse and predicting prognosis
    We were the first to develop a molecular test to detect cancer recurrence that is sensitive enough to find one blood-cancer cell among a million normal cells — an accomplishment that saves lives. This test allows doctors to quickly prescribe new therapy at the first hint of possible relapse. We're developing similar tests that can predict a patient's response to treatment so that doctors can customize therapy and ensure the best chances for survival.

    Cord-blood transplants extend lifesaving options to more patients
    About a third of all blood-cancer patients who could benefit from a transplant are unable to find a compatible donor, a number that is much higher for patients with rare tissue types or who are of mixed ethnicity. We're pioneering new transplants based on umbilical-cord blood, which does not need to be as stringently matched to a patient's tissue type as other sources of blood stem cells.

    Quality of life counts
    We house the world's leading long-term follow-up program for blood-cancer patients, which provides outstanding ongoing medical and psychosocial support for the unique needs of transplant survivors. The program's research has yielded major reductions in complications following treatment and helps survivors adjust to life after cancer therapy.
    The future is brighter with your help

    Every day brings us closer to new discoveries that will benefit more blood-cancer patients like Steve Ross—and private donations are essential to our progress.