Testing is curbing some genetic diseases

February 17, 2010 at 12:00a.m.

Associated Press

Some of mankind’s most devastating inherited diseases appear to be declining, and a few have nearly disappeared, because more people are using genetic testing to decide whether to have children.

Births of babies with cystic fibrosis, Tay-Sachs and other less-familiar disorders have dropped since testing came into wider use, The Associated Press found from a review of studies and interviews with numerous geneticists and other experts.

Many of these diseases are little known, and few statistics are kept. But their effects — including blood disorders and muscle decline — can be disabling and often fatal during childhood.

Now, more women are being tested as part of routine prenatal care, and many end pregnancies when diseases are found. One study in California found that prenatal screening reduced by half the number of babies born with the severest form of cystic fibrosis, because many parents chose abortion.

More couples with no family history of inherited diseases are getting tested before starting families to see if they carry mutations that put a baby at risk. And a growing number are screening embryos and using only those without problem genes.

The cost of testing is falling, and the number of companies offering it is rising. A 2008 federal law banning gene-based discrimination by insurers and employers has eased fears.

Genetic testing pushes hot- button issues: abortion, embryo destruction and worries about eugenics — selective breeding to rid a population of unwanted traits. Yet it is touching a growing number of people:

UIn suburban Cleveland, Beth and Thad Meese were stunned to learn during her second pregnancy that they carry genes that can cause cystic fibrosis. Tests show the baby won’t have the disease, but they have decided against having a third child or to screen embryos if they do.

UIn Boston, Harvard psychologist and author Steven Pinker and his wife, novelist Rebecca Goldstein, learned last year that they carry genes that cause a serious neurological disease, familial dysautonomia. Too old to have children, they shared the news with younger relatives, who are being tested to see if they, too, have the gene.

UIn Vancouver, Canada, Jeff and Megan Carroll screened embryos to have two children free of the Huntington’s disease gene Jeff has. “I felt very strongly that I didn’t want to pass on this,” he said. Huntington’s “is done killing people in my family when I am gone.”