Before this BBC podcast kicks off, I'd like to tell you about some others you might enjoy.

My name's Will Wilkin and I Commission Music Podcast for the BBC.

It's a really cool job, but every day we get to tell the incredible stories behind songs, moments and movements.

Stories of struggle and success, rises and falls, the funny, the ridiculous.

And the BBC's position, at the heart of British music

means we can tell those stories like no one else.

We were, are and always will be right there at the centre of the narrative.

So whether you want an insightful take on music right now

or a nostalgic deep dive into some of the most famous and infamous moments in music,

check out the music podcasts on BBC Sounds.

Welcome to the inquiry from the BBC World Service. I'm Tanya Beckett. Each week, one question,

four expert witnesses and an answer. In August of last year, a baby boy was born in a hospital in Philadelphia in the United States.

He looked healthy, but very quickly it became clear something was wrong.

He was sleeping too much and wasn't eating.

Blood tests showed that baby KJ had sky-high levels of ammonia in his body. The root cause was his genes,

or more particularly, a specific gene mutation that didn't allow his liver to expel the ammonia.

Doctors and scientists entered a race to try to treat him before his condition led to a coma.

In a few short months, they had designed and gained government approval for a gene editing drug tailored specifically to him.

Earlier this year, baby KJ received three infusions, each a month apart, containing

billions of microscopic gene editors that honed in on the mutation in his liver. He became

the first ever recipient of a gene therapy designed to treat a single person. KJ will need to be monitored for

the rest of his life, but a few months after the treatment, his health improved beyond recognition.

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