Infant DNA tests speed up diagnosis of rare diseases
From the day she was born, the girl had seizure after seizure. Doctors at Kansas hospital tried to keep her alive. Weeks passed and every medication failed. Finally, her family decided to let their baby go, and the medical devices were withdrawn. She was five weeks old.world Updated: Oct 15, 2012 02:00 IST
From the day she was born, the girl had seizure after seizure. Doctors at Kansas hospital tried to keep her alive. Weeks passed and every medication failed. Finally, her family decided to let their baby go, and the medical devices were withdrawn. She was five weeks old.
Doctors suspected a genetic disorder, and as it happened the hospital had just begun a study of a new technique for quickly analysing the DNA of newborns, zeroing in on mutations that can cause disease.
This new method, published on October 3 in Science Translational Medicine, the magazine, is a proof of concept — a demonstration in four babies that it is possible to quickly scan a baby’s entire DNA and pinpoint a disease-causing mutation in a couple of days instead of weeks or months.
The study’s investigators said the test could be one of the first practical fruits of the revolution in sequencing an individual’s entire DNA.
For the baby with seizures, her doctors provided a sample of her blood. The analysis took only 50 hours. The baby had a mortal gene mutation so rare that it had been reported just once before.
The idea behind the test is to take advantage of what is known about disease symptoms to narrow the search for genetic aberrations.
Although more research needs to be done before the test is ready for widespread use.
To test the method, investigators tried it with two babies whose disease had been diagnosed only through an autopsy. They found the genetic causes. Then they tried the method on four babies who were seriously ill with suspected genetic diseases. They quickly found the mutated gene in three of the four.
In sequencing and analysing the entire DNA, researchers may discover, for example, aberrations leading to conditions that occur only in adults. Do parents really want to know that their sick baby has a gene that increases the risk of Alzheimer's disease?
However, the method is expensive, costing about $13,500 and is not yet covered by insurance.