07/27/2011 01:53 pm ET | Updated Sep 26, 2011

Genetic Mapping Helped These Twins Lead Normal Lives

Fourteen-year-old California twins Alexis and Noah Beery have the rare neurological movement disorder dystonia, but are leading symptom-free, normal lives today because of a scientific feat -- human genome mapping.

Using blood samples, they had their entire genetic codes mapped by Baylor Genome Sequencing Center scientists, who were able to pinpoint the exact gene that was responsible for their disease, the Early Show reported. And with the knowledge of what gene was the culprit, doctors were able to prescribe the exact tailored medicine they needed to keep the disease under control.

The Beerys knew something wasn't right with their twins before their dystonia diagnosis. Alexis couldn't sleep during the night and had coordination problems and seizures. And Noah threw up several times a day, the Early Show reported.

Coming to the diagnosis of dystonia was not easy. At age 2, the twins were diagnosed with cerebral palsy, but their mother Retta always suspected the diagnosis wasn't correct because Alexis's symptoms kept on getting worse.

Finally, the twins were diagnosed with dystonia at five years old, and received treatment for the disorder. However, their dopamine treatments only had limited success, and Alexis was suffering from severe breathing problems.

"We almost lost her a couple of times," mother Retta Beery said on The Early Show. "We had the paramedics in our house trying to get her breathing again."

That's when the family went to Baylor to get genetic code mapping to come up with a more targeted treatment, the Early Show reported.

There, it was discovered that the twins had a mutated gene that didn't make enough dopamine and serotonin (another neurotransmitter), Reuters reported. Starting the twins on a supplement that replenished the serotonin, in addition to their dopamine medication, helped squash the symptoms.

The decoding of the entire human genome was completed in 2003. Also called genetic mapping, it allows scientists to pinpoint the exact gene that is responsible for a genetic-based disease, and where exactly on the chromosome the mutation is located, according to the National Human Genome Research Institute. The mapping is done by collecting blood or tissue samples from family members, in order to see what DNA patterns are similar among the family members with the particular disease.

However, genetic mapping isn't cheap -- it can cost up to $100,000. And it's not meant for all diseases, just those where a single gene is the culprit, according to the Early Show. But doctors hope that the procedure will become cheaper as years go on, potentially bringing the costs down to $1,000.