Results from a study observing myotonic dystrophy type 2 (DM2) patients has helped pinpoint which disease symptoms are most important to patients with this rare type of muscular dystrophy. According to the study authors, the findings could help create a roadmap for doctors to prioritize treatments. The study titled “Patient-Reported Impact of Symptoms in Myotonic Dystrophy Type 2 (PRISM-2)” was recently published in the journal Neurology.
“This study represents the first large-scale attempt to obtain direct patient input to identify the most prevalent and life-altering symptoms of myotonic dystrophy type 2,” study lead author Chad Heatwole, M.D., University of Rochester Medical Center (URMC) neurologist, said in a recent news release. “This information helps us to better understand the complexities of the disease from a patient’s perspective, and may ultimately prove useful in the clinical management and early diagnosis of patients with this condition.”
Myotonic dystrophy type 2 (DM2) is an autosomal dominant adult muscular dystrophy caused by an abnormal CCTG repeat expansion in the cellular nucleic acid binding protein (CNBP) gene (also known as the zinc finger protein 9 [ZNF9] gene) on chromosome 3. Clinically, DM2 produces a multisystemic and diverse set of symptoms. Frequently reported DM2 symptoms include pain, progressive weakness, myotonia, cataracts before age 50, hypogonadism, cognitive impairment, cardiac arrhythmias, tremor, hypersomnia, and fatigue.
While DM2 shares many identical clinical characteristics with myotonic dystrophy type 1, there are differences in symptoms including prominent pain and a different pattern of weakness that more commonly originates in the upper arms, legs, and back muscles. Many doctors, including neurologists, are unfamiliar with DM2 as it is often confused with DM1 and other syndromes including fibromyalgia. Consequently, patients with the disease often go undiagnosed for a decade or more.
To determine the frequency and relative importance of the most life-affecting symptoms in myotonic dystrophy type 2 (DM2) and identify the factors that have the strongest association with these symptoms, the research team selected patients from a national database of muscular dystrophy patients developed by URMC. A total of 74 DM2 patients were asked to complete surveys asking them to rate 310 identified DM2 symptoms. The results revealed that the symptoms with the highest prevalence in DM2 patients were the inability to do activities (94.4%); limitations with mobility or walking (89.2%), hip, thigh, or knee weakness (89.2%); fatigue (89.2%); and pain (79.7%). Importantly, inability to conduct activities and fatigue were the symptoms that DM2 patients reported to have the greatest impact on their lives.
“These findings demonstrate that the symptoms that are the most prevalent in this population are not always the ones that are most important to the patient,” said Heatwole. “This is an important distinction and understanding which symptoms matter most to patients will help physicians navigate the myriad of treatment options and develop strategies that reduce the burden of the disease.”