DISEASES
Scintillating health clues
Skin cancer triples in women under 40
The incidence of two types of skin cancer has tripled in women under 40, a sign that tanning is still popular among the young despite warnings about the harm it can cause. The rate of basa cell and squamous cell cancer rose to 32 per 100000 women under 40 as compared to 13 per 100000 in 1970’s the study says. Tan is still accepted as a sign of health and beauty and so changing that message that fair skin as very healthy and beautiful, said study author, Dr. Leslie Christenson of Mayo Clinic in Rochester, Minnesota.
Genetic Diseases
OUR IMMUNE SYSTEM:
THE WARS WITHIN
By Peter Jaret
Every minute of every day wars rage within our bodies. The combatants are too tiny to see. Some, like the infamous virus that causes AIDS, or acquired immune deficiency syndrome, are so small that 230 million would fit on the period at the end of this sentence. Yet they employ tactics that can vanquish the much larger cells they swarm upon.
Usually we never even notice the battles in the incessant wars within us. We have evolved legions of defenders, specialized cells that silently rout the unseen enemy. Sometimes these warriors mistake harmless invaders, such as pollen, for deadly foes, and they mount an allergic reaction. Sometimes our defenders are caught unprepared, and we develop a cold, the flu, or worse. Occasionally some of our own cells begin the mutinous proliferation of cancer and manage to evade the surveillance of our body's defense forces. But for every successful penetration of our defenses, thousands of attempts are repelled. We sleep securely, trusting the invisible vigilantes of our immune system.
For decades immunology—the study of the immune system—was a backwater of medicine. In reality we did not have the instruments to explore the battlefields within us. In the past 20 years, however, powerful microscopes and improved laboratory techniques have helped detail the strategies of both defenders and foes. By 1980 it had become clear that immunology held great promise for treating diseases as diverse as cancer and arthritis.
Counseling
WHO BENEFITS FROM GENETIC COUNSELING
Many prospective parents use genetic counseling to help resolve issues surrounding pregnancy and infertility. Genetic counseling is helpful to parents who already have a child with a genetic disorder so they can learn more about the condition and the chance that their other children may be affected. People with a family history of life-threatening diseases may consult a genetic counselor to learn the probability that they will develop a disease. Others seek genetic counseling to determine the likelihood that they will develop a disease that occurs more frequently in their ethnic group.
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Genetic Counseling
INTRODUCTION
Genetic Counseling, medical specialty that helps parents and prospective parents evaluate and cope with their risk of passing hereditary disorders to their children. Genetic counseling also helps individuals assess the possibility that they will get a medical condition known or suspected to have a genetic basis, such as Huntington’s disease, breast cancer, or Alzheimer’s disease.
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A Prospective Parents
A couple that is thinking about conceiving a child may want to consider genetic counseling for several reasons. For instance, many women aged 35 or older seek genetic counseling because they are at a higher risk than younger women of giving birth to a child with a chromosomal abnormality. These abnormalities occur when a child inherits all or part of an extra copy of a chromosome. Down syndrome, the most common chromosomal disorder, is almost nine times more common in babies born to women aged 40 than those born to women aged 30. Couples who already have a child who was born with a genetic disorder may seek genetic counseling to determine the risk that future children may be similarly affected.
Expecting couples concerned about the health of their unborn baby may request genetic counseling to learn if the baby is at risk for a disease. A pregnant woman may worry that she has been exposed to factors that can hurt the development of her fetus, such as infectious diseases, medications, alcohol, nonmedical drugs, or radiation. Genetic counseling can prove useful when adopting a child. Parents interested in adopting a child whose biological parent or grandparent has an inherited condition may seek counseling to determine if this family history is likely to affect the child.
Inheritance Patterns
Inheritance Patterns
As part of the diagnosis process, genetic counselors educate clients about the inheritance patterns of suspected genetic disorders, many of which are rare conditions unfamiliar to most people. Genetic disorders typically arise from single gene mutations or chromosomal abnormalities that are transmitted from generation to generation (see Genetics).
Each individual inherits two versions of every gene, one from the mother and one from the father. Occasionally one gene in a pair becomes altered through a process called mutation, and this mutated gene passes from parent to child in a predictable pattern (see Heredity). In some cases, the mutated gene inherited from one parent dominates, expressing itself even when a normal gene inherited from the other parent is present. A parent who has the mutated gene develops the disease and has a 50 percent chance of passing the faulty gene on to his or her child. Examples of diseases caused by dominant genes include neurofibromatosis and Huntington’s disease.
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Other diseases are caused by recessive genes, such as sickle-cell anemia and cystic fibrosis. Such diseases develop when both genes of a pair have a mutation. Two parents who each carry a mutated recessive gene for the same disease have a 25 percent chance with each pregnancy of having a baby who will develop the disease. A parent may unknowingly carry a mutated recessive gene for a particular disease without suffering any symptoms of the disorder.
Single gene mutations may occur on the sex chromosomes, the pair of chromosomes in each cell that determine the sex of an individual. Females’ sex chromosomes consist of two X chromosomes, and males have one X and one Y chromosome. A female with a recessive mutated gene on one X chromosome usually has a normal gene on her other X chromosome, and the normal gene masks the effects of the mutated gene. As a carrier of the mutated gene, the female has a 50 percent chance
