U.S. scientists have sequenced the entire genetic code of four gravely ill newborns and identified genetic diseases in three of them in two days, quick enough to help doctors make treatment decisions.
Doctors behind the preliminary study released on Wednesday say it demonstrates a practical use for whole-genome sequencing, in which researchers analyze all 3.2 billion chemical "bases" or "letters" that make up the human genetic code.
"It is now feasible to decode an entire genome and provide interim results back to the physician in two days," said Dr. Stephen Kingsmore, director of the Center for Pediatric Genomic Medicine at Children's Mercy medical centre in Kansas City, Missouri, whose study was published in the journal Science Translational Medicine.
The study tested two software programs developed at Children's Mercy and used with a high-speed gene sequencer from Illumina called HiSeq 2500, which can sequence an entire genome in about 25 hours. The company helped pay for the study and company researchers took part in it.
Typically, genetic testing on newborns using conventional methods takes four to six weeks, long enough that the infant has either died or been sent home. In the study, the team tested the system on four seriously ill babies whose conditions were suspected of having a genetic cause. Only one is still alive, a boy born with a rare heart defect that the team discovered is shared by the child's six-year-old brother. The infant underwent heart surgery.
The testing also was able to diagnose a rare form of epilepsy in a baby girl, and identify the likely cause of a lethal skin condition in a baby boy.
