Conventional methods require months of laboratory work while karyomapping takes less than a fortnight and is able to detect more than -200 disorders. Lucas' mother Carmen, 26, who works in recruitment, inherited - Charcot-Marie-Tooth disease from her father who suffered with the illness all his life.
It causes weakness and wasting of the muscles below the knees and often those of the hands and can lead to loss of feeling in the fingers and legs.
Although Mrs Neagu only has mild symptoms, she was concerned that her children would inherit the disease and specialists warned that there was a 50 per cent chance she would pass on the illness.
"For me the risk was too high," she said. "My dad had severe symptoms and it really got him down. He was unable to walk unaided and he always felt people were looking at him and staring. It had a massive impact on him mentally.
"I was told I could try and get pregnant and have a test at 16 weeks, but that really wasn't an option for me because it would have been too hard to have an abortion at that stage.
"Then we were told about a clinic in London which could screen the disease out, and we felt we had to try."
To isolate the genes responsible for Charcot-Marie-Tooth disease, doctors took DNA swabs from Mrs Neagu, her mother and Lucas's father Gabriel, 30, who works in sales for Vodafone.
They then compared the gene sequences at 300,000 - different points of the chromosomes to work out which - section of genetic code was defective and responsible for causing the abnormality.
The couple then underwent a normal IVF cycle but, - crucially, the embryos created from the procedure were biopsied to find out which ones were free of the genetic disease.
The test also checks that embryos have the right number of chromosomes, a frequent cause of miscarriage and developmental disorders, such as Down's syndrome.
The procedure started in December 2013 and Lucas was born a year later. He is now three-months-old, happy and healthy.
Mrs Neagu added: "Lucas is absolutely perfect. He is really big for his age, and healthy. I have peace of mind now that he is going to be okay.
"I obviously worry, like all mother's, but now I worry about normal things. I know for sure that he is not only free of Charcot-Marie-Tooth disease but also other illnesses.
"I recommend it to any other mother who is -worried about passing on an illness."
The procedure is available on the NHS, giving hope to parents concerned about passing on serious genetic faults to their children.
Mr and Mrs Neagu froze two more embryos during the first round of IVF and is planning to have at least one more child within five years.
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