Myotonic Dystrophy
Type 1 (DM1)

Myotonic dystrophy type 1 (DM1) is a rare, genetic, progressive muscle disease distinguished by myotonia. People living with DM1 typically experience progressive weakness of major muscle groups, which can affect mobility, breathing, heart function, speech, digestion and vision as well as cognition. The severity of symptoms and pace of progression varies. There are currently no disease-modifying therapies approved to treat DM1.

Read on to learn about one family’s experience with DM1.

Each person living with DM1 has a unique and powerful story to tell

Meet Joachim Boekelmann

Joachim Boekelmann and his family

“I’m not alone in this”: One person’s journey with DM1

Growing up, Joachim Boekelmann says, myotonic dystrophy “was always in my background, and in the back of my head.”

His father was diagnosed in his 40s with the inherited muscle-wasting disease, meaning that Joachim and his sister each had a 50-50 chance of carrying it. Joachim took a genetic test and learned that he was a carrier. His sister was later diagnosed, too.

At the time, Joachim had no symptoms. Doctors said they would begin to appear at some point. Exactly when was anyone’s guess.

“In a way, it was a shock, but not really,” recalls Joachim, now 51. “It confirmed what I had thought was possible.”

Joachim, living with DM1

In 2005, at age 37, he was officially diagnosed with DM1.

“It took me a long time to accept the disease,” says Joachim, who works as an attorney at a reinsurance company and lives with his wife and two children, ages 21 and 15, in a ranch-style house with no stairs in Princeton, NJ. “I’m trying to do as many things as I can. My wife might ask me if I need help with opening a jar or a yogurt cup, and often I’ll say no. I don’t always want to admit that I cannot do a certain thing.”

Indeed, Joachim’s disease can make everyday activities a challenge. He walks slowly, and sometimes trips and falls. His speech is nasally, which can occasionally make him hard to understand. A German native who has always enjoyed traveling, Joachim can no longer lift a moderately heavy suitcase, and sometimes has trouble opening the car door. A weak grip has made one of his favorite hobbies – building model trains – more taxing.

Joachim says his sister’s symptoms are even more severe. And he remembers the physical and emotional toll that DM1 took on his father; by the time he died at age 75, he couldn’t walk, dress or feed himself.

Joachim also knows there is a chance that his children might carry the disease, too. His son Max is currently undergoing testing.

“I am very optimistic that an effective treatment for DM1 will be found.”

DM1 is a rare, progressive muscle disorder distinguished by myotonia, or muscle cramping with slow release. People living with myotonic dystrophy type 1 typically experience progressive weakness of major muscle groups, which can affect mobility, breathing, heart function, speech, digestion and vision as well as cognition. The severity of symptoms and pace of progression varies from person to person, but becomes more severe as it is passed down to from generation to generation. There is no cure for DM1, which affects approximately 1 out of every 2,500 people to 1 in 8,000 people in the United States and Europe, affecting over 40,000 people in the United States and over 74,000 people in Europe.

For Joachim, the symptoms began in his early 30s: first myotonia, followed by weakness in his hands and difficulty swallowing. His shoulder blades would protrude when he lifted his arms.

Joachim, living with DM1

“That’s the scary part – what lies ahead?” Joachim says. “I saw my dad, how he deteriorated. I have seen how my sister has deteriorated over the last couple of years. What lies ahead five or ten years from now?”

Despite the uncertainty, Joachim draws strength from his family and inspiration from other patients living with DM1 whom he has met through Myotonic, the world’s largest patient organization focused solely on myotonic dystrophy. “You get the sense, I’m not alone in this,” he says of events like a Myotonic conference that he attended in 2014.

Joachim says he does not want to be defined by DM1. He has tried to remain as active and independent as possible. Through all of the daily challenges, his support network and personal faith have helped him persevere.

Meanwhile, he believes that finding a cure is a matter of when – not if.

“Given the research developments of the past few years and the number of drug makers that are actively involved in the research,” Joachim says, “I am very optimistic that an effective treatment for DM1 will be found.”

About Myotonic Dystrophy Type 1


Disease symptoms can begin at any point in an affected person’s life, depending on the DM1 subtype. Adult-onset DM1 symptoms typically appear in early teens to 50 years of age.


The underlying cause of DM1 is a defective DMPK gene that encodes a mutated RNA. DM1 is known as a triplet repeat disease because of the expanded number of CTG repeats in the DMPK gene. These CTG repeats cause toxic RNA to cluster in the nucleus. The toxic RNA binds to RNA splicing proteins, causing altered splicing events in many other genes. This altered splicing results in the wide range of disease symptoms and contributes to the significant disease burden.


Patients experience a broad spectrum of symptoms, including:

  • Muscle weakness throughout the body, from difficulties with facial and swallowing muscles to hand and grip weakness to lower leg and foot weakness, foot drop and resulting mobility issues
  • Myotonia, or difficulty relaxing muscles in the jaw, tongue, throat muscles, lower arm and hand
  • Respiratory issues
  • Gastrointestinal dysfunction throughout the GI tract
  • Cognitive deficits, excessive daytime sleepiness and dysregulated sleep
  • Early cataracts


There are currently no disease-modifying treatments for DM1.


For more information about myotonic dystrophy, see these additional resources:

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