Gene therapy carries the promise of cures for many diseases and for types of medical treatment that didn't seem possible until recently. With its potential to eliminate and prevent hereditary diseases such as cystic fibrosis and hemophilia and its use as a possible cure for heart disease, AIDS, and cancer, gene therapy is a potential medical miracle-worker.

But what about gene therapy for children? There's a fair amount of risk involved, so thus far only seriously ill kids or those with illnesses that can't be cured by standard medical treatments have been involved in clinical trials using gene therapy.

As those studies continue, gene therapy may soon offer hope for children with serious illnesses that don't respond to conventional therapies.

Our genes help make us unique. Inherited from our parents, they go far in determining our physical traits like eye color and the color and texture of our hair. They also determine things like whether babies will be male or female, the amount of oxygen blood can carry, and the likelihood of getting certain diseases.

Genes are composed of strands of a molecule called DNA and are located in single file within the chromosomes. The genetic message is encoded by the building blocks of the DNA, which are called nucleotides. Approximately 3 billion pairs of nucleotides are in the chromosomes of a human cell, and each person's genetic makeup has a unique sequence of nucleotides. This is mainly what makes us different from one another.

Scientists believe that every human has about 25,000 genes per cell. A mutation, or change, in any one of these genes can result in a disease, physical disability, or shortened life span. These mutations can be passed from one generation to another, inherited just like a mother's curly hair or a father's brown eyes. Mutations also can occur spontaneously in some cases, without having been passed on by a parent. With gene therapy, the treatment or elimination of inherited diseases or physical conditions due to these mutations could become a reality.

Gene therapy involves the manipulation of genes to fight or prevent diseases. Put simply, it introduces a "good" gene into a person who has a disease caused by a "bad" gene.

The two forms of gene therapy are:

Currently, gene therapy is done only through clinical trials, which often take years to complete. After new drugs or procedures are tested in laboratories, clinical trials are conducted with human patients under strictly controlled circumstances. Such trials usually last 2 to 4 years and go through several phases of research. In the United States, the U.S. Food and Drug Administration (FDA) must then approve the new therapy for the marketplace, which can take another 2 years.

The most active research being done in gene therapy for kids has been for genetic disorders (like cystic fibrosis). Other gene therapy trials involve children with severe immunodeficiencies, such as adenosine deaminase (ADA) deficiency (a rare genetic disease that makes kids prone to serious infection), sickle cell anemia, thalassemia, hemophilia, and those with familial hypercholesterolemia (extremely high levels of serum cholesterol).

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Gene Therapy and Children - KidsHealth