Global Genes reports that 24 million people in the US are living with rare diseases of genetic origin, and about 30% of children with a rare disease will not live to see their fifth birthdays.
A recent news release from the American College of Medical Genetics and Genomics (ACMG) notes that "carrier screening for inherited genetic disorders is an important part of preconception and prenatal care for the nearly 4 million women who give birth in the US annually," and that "new technology in genotyping and genetic sequencing allows for more efficient carrier screening of a greater number of conditions simultaneously."
Doctor's alert: people want to know more about their genes
In a new study of American adults' knowledge of and attitudes toward genetic testing, 53% of the respondents wanted to know what's in their DNA, and 70% wanted to find out if they could pass on a genetic disease. Their doctors, however, do not seem to be on the same page, as only 7% of respondents said their physicians had discussed genetic screening with them.As Dr. Francis Collins, director of the National Institutes of Health, wrote in 2010: "It is likely that within a few decades people will be puzzled and dismayed, as I am now, that our health care system put so many couples in an unnecessarily difficult position, by not identifying their carrier status until a pregnancy was already underway."
How genetic testing works
Genetic tests use a sample of blood or saliva, which is usually collected at a physician's office or a lab. The conditions the sample is screened for can depend on a person's ethnic background, family history, previous pregnancies and the physician's recommendations.Everyone carries at least six changed genes, which could potentially cause a genetic disorder for a couple's children, particularly if a partner is a carrier for the same genetic condition. Some diseases, such as Duchenne Muscular Dystrophy and Fragile X, are called X-linked conditions and are associated with mutation on the X chromosome.
Mothers who are carriers for an X-linked disorder have a 50% chance of passing the changed gene to each of their children. Because boys only have one copy of the X chromosome, which is inherited from their mother, they are usually severely affected.
Rarely, girls will have symptoms if they inherit the changed gene from their mothers, but usually they have no symptoms. Most people are carriers of at least one recessive or X-linked genetic condition.