I was told my daughter would never walk because of a rare genetic disease. We just strolled down the catwalk together at New York Fashion Week.

• Amber-Joi Watkins' daughter, Céline, has spinal muscular atrophy.
• Céline is among the first patients treated with new medications and therapies.

This as-told-to essay is based on a conversation with Amber-Joi Watkins. It has been edited for length and clarity.

This week, I strolled down a runway at New York Fashion Week. At my side, my 4-year-old daughter, Céline, walked with her beautiful, swaying gait. It would have been a banner moment for any mom of a fashion-forward girl. But for me, it was truly a dream.

Céline has a rare genetic condition called spinal muscular atrophy, or SMA. People can get it at any point in life, but hers was present from birth. The disease destroys neurons and leads to muscle weakness that threatens basic bodily functions like breathing and eating. When Céline was 6 months old, I was told she would never walk. I couldn't have imagined I'd ever see her on the runway so happy and healthy.

We were lucky to get a diagnosis quickly

When Céline was 3 months old, I enrolled us in mommy-and-me yoga. I noticed that the other babies were kicking, rolling, and holding up their heads during tummy time, but she wasn't doing any of that. I asked her pediatrician about it, but she told me that babies developed at different rates and Céline was perfect. I had to agree.

But by the time Céline was 6 months old, she still wasn't moving much. We saw another pediatrician, who immediately suspected SMA. Most SMA families have a long road to diagnosis, but we were incredibly lucky. Céline was diagnosed within a week and started treatment a week after that.

The medicines for SMA are so new that the doctor asked my husband and me if we wanted to treat the SMA or let it run its course; but without treatment, Céline's life expectancy was about 2 1/2 years. Of course, our decision was to try anything to save her.

We aren't sure what the future holds

Once we started treatment, we immediately saw improvements. It wasn't a cure, but it was progress.

Because Céline got intervention so young — which seems to be slowing the progress of her disease rapidly — doctors aren't sure what her prognosis is. We focus on the fact that she's doing so well right now.

SMA treatments have advanced so much in the past decade. If Céline had been born sooner, she may not have survived childhood. I am so grateful for medical research. I feel like I've won the lottery.

I decided to speak out

For the first six months after Céline's diagnosis, I was so overwhelmed that I didn't want to talk to anyone about it. Then, I decided to start sharing my story. After Céline was diagnosed, I could find only tragic stories of doom and gloom. If another parent had this diagnosis, I wanted to offer hope. I didn't want them to feel the same crushing fear I had felt.

I eventually connected with SMA My Way, an organization that supports people affected by SMA. Last year, we produced a song, "Spaces," that was by people with SMA for people with SMA.

This year, we organized the Double Take fashion show during New York Fashion Week. The name has a deeper meaning. People often do a double take toward people with SMA, who are often in a wheelchair or walk with a swaying gait like Céline. We flipped the phrase on its head and made the double take about our fashion and taking back our power.

Now that our fashion show is finished, we're living it up in New York City. Céline has been to FAO Schwarz and all the other iconic kids stores. She's loving every minute of it, and I am, too. SMA often leads to a shortened lifespan. I don't think about what the future holds — I can't. But when you get a diagnosis like SMA, you start living life to the fullest. That's what Céline and I do.