Baby’s Genetic Code Mapped In Womb

An unborn baby’s whole genetic code has been mapped in the womb using DNA taken from its parents.

The technique could in future make it possible swiftly to scan for some 3,500 genetic disorders before birth, without physically disturbing either foetus or mother.

Most pre-natal genetic screening currently involves tapping fluid from the foetal sac, or taking placental samples. This is done by either inserting a probe through the mother’s abdomen or the neck of her womb.

Such invasive methods can only identify a small number of birth defects including Down’s syndrome, spina bifida, cystic fibrosis and muscular dystrophy. They also pose risks for both mother and child.

The new research involved analysing DNA shed by the foetus and floating in the mother’s bloodstream. Blood sample DNA from the mother was also studied as well as DNA extracted from the father’s saliva.

Fitting pieces of the genetic jigsaw together, scientists in the US were able to reconstruct the entire genetic code of an unborn baby boy.

The findings, reported in the journal Science Translational Medicine, were checked by looking at the baby’s DNA after birth.

Researchers were also able to identify 39 of 44 “de novo”, or new, genetic mutations before the baby was born.

De novo mutations, which are not inherited, are responsible for a large percentage of genetic disorders. They are thought to play a role in a number of complex conditions such as autism and schizophrenia.

Lead scientist Dr Jay Shendure, from the University of Washington in Seattle, said: “This work opens up the possibility that we will be able to scan the whole genome (genetic code) of the foetus for more than 3,000 single-gene disorders through a single, non-invasive test.”