Keith McArthur and his son Bryson on the first day of school 2017. Bryson has GRIN1, a rare genetic condition.

Getting a GRIN1 Diagnosis

In December of 2015, my son Bryson was diagnosed with GRIN1, a rare genetic condition. A blog post I wrote about the diagnosis has become the most popular piece on my previous blog, with more than 5,000 views.

Because GRIN1 is so rare, doctors tend not to know much about the condition so families are desperate for information. They turn to Dr. Google, and my post is one of the few non-technical results they find. Dozens of families have reached out to me this way and I’ve forward them on the the GRIN1 support group on Facebook.

I want to do a better job of helping these families when they first get the diagnosis. Over the next few days, I’m going to share more about GRIN1. I’m starting today with my reflections a few days after we got the diagnosis.

Laura took a deep breath and mustered up the courage to call the neurology clinic.

Families of sick children were supposed to wait patiently. The clinic nurse had made this clear eight weeks earlier when Laura first called to check up on Bryson’s lab results.

But parents quickly learn that it pays to be pushy. And what was supposed to be a four-month wait had stretched to half a year of waiting to find out if Bryson had tested positive for a degenerative disease that would prevent him from reaching adulthood. So Laura ignored the ‘don’t call us; we’ll call you’ directive and dialed again.

“The results still aren’t back,” the nurse said. “We’ll call you when they are.”

When Laura pressed, the nurse reluctantly agreed to check on the file. A few minutes later, the nurse returned to the phone to sheepishly acknowledge that an error had been made. Bryson’s blood was never sent to the US lab for testing.

The reality of this – another four months of waiting – hit Laura hard. She hung up the phone and wept.

Four months later, the results finally came back. They were negative.

For nearly a decade, Bryson has endured countless tests to try to uncover a diagnosis: A muscle biopsy. Multiple MRIs and EEGs. Dozens of blood and genetics tests. One by one, we crossed potential diagnoses off the list as every test came back negative.

But a few days ago our world changed. Through a full sequencing of Bryson’s DNA, we have a diagnosis. Bryson has an extremely rare genetic disorder known as GRIN1, named for the gene that is misspelled.

It’s so rare that our doctors don’t really know much about it. And there’s very little on the Internet about it. But through social media, we’ve already connected with families in the United States and Europe who have children with this diagnosis.

While details vary from person to person, the common symptoms include moderate to severe intellectual disability and low muscle tone. Many kids also have seizures. Interestingly, several of these children find joy watching sports.

And the good news: the disease isn’t degenerative. GRIN1 kids progress and develop in physical and mental ability at their own pace.

Our kind and brilliant genetics doctor, Ronald Cohn, confided he’s been surprised over the years at how happy families are to receive a diagnosis – even when it doesn’t change treatment.

And indeed, getting a diagnosis has changed our world.

Laura has always felt like maybe the pregnancy was her fault – that she did something wrong when Bryson was in her belly. The pressure on expectant mothers to be perfect is immense. Now she can finally let go of this toxic guilt.

And for me? I understand now that Bryson’s little body is doing exactly what it’s supposed to be doing given his own genetic code. He is perfect. Yes, one of his genes is coded differently, but the vast majority – some 20,000 – are copies of mine and Laura’s.

Not only that, but we now have the knowledge that in the future, there could possibly be new treatments – medicines or gene therapies – that could help Bryson to progress more quickly.

The biggest change, however, is that our family is finally part of a community. It’s a small community; we know of just eight other people with the disease. But we are no longer alone.

Bryson will never be alone.

I’ve shared posts about Bryson before, here and here. The photo above is of Bryson and me on his first day of school. Isn’t he such a handsome little dude?


  1. We cry each time we read this blog. Bryson is so lucky to have the wonderful family that he was given and in the alternative we know that you are so very lucky to have him. He lights up our lives each time he smiles.

  2. Our son has just today been diagnosed with Grin1. We live in UK. can you signpost me to any groups please?

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