Let's turn now to a promising medical breakthrough.

Doctors announced this week they have treated a newborn baby with a rare genetic disease using the world's first personalized gene editing treatment.

In the arms of his parents, Nicole and Kyle, KJ Muldoon looks much like any other happy, healthy nine-month-old baby.

But just days after he was born, his parents were initially given alarming news.

One of the doctors came to us and said, we think we know what's wrong.

Your son is very sick.

But the best place in the world for your child to be when he's very sick is next door.

Doctors at the Children's Hospital of Philadelphia told them that their son had a rare

genetic disease known as CPS1.

It only affects one in 1.3 million babies, but the disease caused by a single mutation in

his DNA meant their child's body couldn't process ammonia and doctors had to carefully restrict

protein in his diet.

You Google CPS1 deficiency and it's either fatality rate or liver transplant.

The choices were stark.

Our child is sick.

We either have to get a liver transplant or do this, given this medicine that's never been given anybody

before, right? I mean, what an impossible decision to make.

Doctors told them they could try a new experimental procedure with KJ, one that had been in the works for years.

Doctors used the gene editing technology known as CRISPR to isolate and correct

that single mutation. In essence, CRISPR technology was used as a kind of GPS to go into the

baby's DNA and use an enzyme to fix just one errant letter out of about $3 billion in his DNA.

Therapy as quickly as essential. Dr. Rebecca Arons Nicholas was one of the leaders of the team.

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