13 January 2011

Gene test finds disease risk in parents

A new test for genetic mutations in parents might help prevent conception of babies with deadly inherited diseases, US researchers reported.


A new test for genetic mutations in parents might help prevent conception of babies with deadly inherited diseases, US researchers reported.

The test

The brainchild of a biotech CEO whose young daughter has a deadly and incurable genetic disease, can detect more than 500 recessive genetic diseases before a child is even a twinkle in the parents' eyes.

In developing the test, the researchers found that people may have an average of two to three recessive genetic mutations that, with bad luck, could give their children one of the diseases.

"The test was designed to check for carrier status –whether a person's genome has a copy of one of 448 diseases that cause catastrophic childhood disease," said Dr Stephen Kingsmore of the National Centre for Genome Resources in Santa Fe, New Mexico.

"The diseases are recessively inherited, which means both parents have to be carriers. If this is the case, they have a one in four chance of having an affected child," added Dr Kingsmore, whose findings are reported online in Science Translational Medicine.

Dr Kingsmore said two companies that make gene sequencers –Life Technologies Corp and Illumina, donated testing for the study. He said the team will use Illumina's test to further develop the product.

Most newborns tested

Most US newborns get tested at birth for a range of genetic diseases such as the metabolic disorder phenylketonuria. And there are tests that adults can take for recessive diseases such as cystic fibrosis and Tay-Sachs disease.

"Tay Sachs, that disease has almost been eradicated by this type of carrier test," Dr Kingsmore said.

But there are hundreds of other diseases that are not tested for. In those cases, people have no idea whether they carry a gene mutation that could put their children at risk.

This happened to Craig and Charlotte Benson of Austin, Texas, whose daughter Christiane has Batten disease.

Batten disease is an incurable nerve disorder that causes seizures, blindness and eventually incapacitates a child, and kills by the late teens or early 20s.

Craig Benson, CEO of Rules-Based Medicine Inc., founded a charity and asked Dr Kingsmore's team to develop a test.

Tests to eradicate diseases

"It is working extremely well in a research setting," Dr Kingsmore said. "It shows that their dream, their vision of having a test that had the potential to eradicate dangerous genetic childhood diseases, is probably feasible."

The test requires more development, and some profits from its sale would eventually be used to fund research, according to Benson's website.

"It's not something we are going to use to get rich," Dr Kingsmore said.

The test has now been expanded to look for more than 500 mutations that cause immune deficiencies diseases, developmental delays, neurological diseases and others.

The test could easily be mass-produced, and costs about $378 (about R2,500), Dr Kingsmore's team reported.

(Reuters Health, Maggie Fox, January 2011)


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