My children have the same degenerative condition. I wish I had gotten genetic-carrier screening earlier to get them treated faster.

• Ashley Pantier has two kids with spinal muscular atrophy, a genetic condition.
• Christopher, 4, uses crutches and braces, while Emily, 1, walks independently.

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

When my son, Christopher, was born nearly five years ago, he hit every milestone until it was time to walk. When Christopher didn't take his first steps by the end of his first year, I was concerned; when he was 15 months, I was even more worried.

By the time he was 18 months old, our doctor shared my concern. He referred us to a physical therapist. But when we started therapy, Christopher got worse, not better. That's when I knew something was really wrong.

We were referred to a pediatric neurologist, but doctor couldn't see us for three months. I was desperate, so I did what all moms do: I went online for answers. That's when I learned about genetic-carrier screening, testing that determines whether a person carries a recessive gene linked to inherited conditions, such as cystic fibrosis and muscular dystrophy.

My obstetrician did the test for me, and my results came back quickly. That's when I learned I was a carrier of spinal muscular atrophy, or SMA, a condition I had never even heard of.

Once I had that result, the pediatric neurologist saw Christopher within three days and diagnosed him immediately.

A life-changing treatment

SMA causes the loss of nerves that control muscle movement. Some children with SMA are unable to eat or breathe. Others, like Christopher, primarily have their movement affected.

SMA is progressive, but there are treatments that stop the progression. Christopher was 20 months when he was diagnosed and 21 months when he started treatment. He immediately stopped getting worse. Then, he began making some improvements: He can now walk with braces and crutches and is able to bear some weight on his legs.

Thanks to medication, Christopher's symptoms won't become more severe. But if he had been diagnosed earlier, he might have been able to walk independently. On the other hand, if I had waited three months for his initial appointment, his complications could have gotten worse.

A road map for care

I was 26 and healthy when I was pregnant with Christopher. My doctor talked to me about screenings, but I declined because I knew that I wouldn't want to terminate the pregnancy no matter what.

I didn't realize then that screenings are a tool: They give you a road map to provide the best possible care for your child.

I was about to see that firsthand. When my daughter, Emily, was born two years ago, she was tested for SMA at just 3 days old, since we knew that my husband and I both carried the gene for the disease. Emily was diagnosed at 5 days old and started treatment at just 5 weeks.

Because Emily had access to treatment sooner, she has been less affected by SMA than Christopher. She darts around the house like a bullet, a bundle of fast toddler energy that we never got to experience with our son.

I wish more parents would consider genetic-carrier screening

Thinking about the things that can go wrong during pregnancy is terrifying. But I wish more parents would consider genetic-carrier screening. About one in four people are carriers of rare genetic diseases. Usually, like in my case, there's no family history of the condition, until there is.

Genetic-carrier screening is noninvasive and gives you the information you need to make the best choices for your family — information that I wish I had access to sooner.