Quick — name three diseases that affect humans. We bet you came up with some of the most well-known, such as heart disease, cancer, Alzheimer’s, and COVID-19. Those are all extremely common, affecting millions of people around the world.

But did you know that the vast majority of known human diseases are actually rare? You’ve probably never heard of most of them. In the U.S., a rare disease is defined as one that affects no more than 200,000 people, or less than one-tenth of one percent of Americans.¹ If these diseases are so rare, why should we care about them?

Because the diseases may be rare individually, but collectively they add up. There are more than 7,000 rare diseases. When you count everyone affected, that’s a staggering 300 million people around the world!

That’s why it is so important to keep an eye on rare diseases. Today is Rare Disease Day, which is celebrated on February 29^th (the rarest of days), or on February 28^th when it’s not a leap year. It’s a day to raise awareness about rare diseases, to honor the families affected, and to celebrate scientists, clinicians, and other stakeholders who are trying to make life better for people with a rare disease.

Myriad Genetics is best known for its work in cancer, but we are also involved in rare diseases through our carrier screening and prenatal screening tests. These genetic screens help families understand their risk of passing inherited rare diseases to their children. The screens also help families detect the earliest signs of a rare disease so they can get much-needed treatment to their babies as soon as possible.

In two recent podcasts hosted by Myriad Genetics’ Chief Medical Officer TJ Slavin, guest speakers offer a compelling look at living with a rare disease. These interviews are a great way to see how genetic testing can help families, especially those who didn’t know about their risk for rare disease.

SMA screening

Spinal muscular atrophy (SMA) is a debilitating condition that affects muscle strength and can cut lives tragically short. Recent innovations in treatment have given people with SMA better outcomes, but early diagnosis is essential and too many people go undiagnosed for years.

In this 12-minute podcast, Ashley Pantier talks about having two children with SMA. The first, Christopher, was 19-months old when he was diagnosed — and it would have been even later if Ashley hadn’t taken a carrier screening test to help determine what was going on. Receiving the test results allowed the family to jumpstart care for Christopher, avoiding months of muscular and nerve deterioration.

Thanks to that diagnosis, Christopher is able to walk with crutches and orthotic braces as long as he gets regular treatment. His little sister, Emily, was also born with SMA, but this time the family knew exactly what to look for. She was tested at birth; at five weeks, she received a new gene therapy for SMA, a one-time treatment that has allowed her to grow and develop like any typical child. “The genetic carrier screening allowed us to make a road map for her so that she could get treated quickly,” Ashley says. “Genetic carrier screening can really change the lives of future kids and their whole families, and it’s really there to help and be a guide and give you information that you didn’t already have.”

ALD answers

Adrenoleukodystrophy (ALD) is a genetic disease that affects the nervous system and adrenal glands, often leading to premature death. In a 20-minute podcast, rare disease advocate Taylor Kane remembers her father, who was diagnosed with ALD in his 40s and died two years later when she was just a child.

Taylor grew up knowing that she was a carrier of ALD, but it was only later that she learned females aren’t simply healthy carriers of ALD. In fact, more than 90% of them get symptoms too.

To help other ALD carriers, and carriers of all X-linked diseases thought to affect males but not females, Taylor launched an advocacy group in 2017 called Remember the Girls. She originally planned to support only ALD, but realized that so many people with other rare diseases were in her same position. “If we brought females from all X-linked diseases together, we would have such a strong community to advocate for our needs,” she says.

Taylor supports the idea of adding ALD to carrier screening panels, noting that many females only find out about their own risk after they’ve had a son diagnosed with the disease. “I see it only as a benefit,” she says.

On this Rare Disease Day, the entire Myriad Genetics team wants families around the world to know that we are here for you. We won’t forget the rare disease community and will continue to provide hopeful parents with genetic insights that will help them make an informed decision when starting or growing their families. Learn more about prenatal genetic screening.

1. Genetic and Rare Diseases Information Center (GARD) https://rarediseases.info.nih.gov/about. Accessed February 2023