A Toxic RNA Catalyzes the In Cellulo Synthesis of Its Own Inhibitor

Researchers from Dr. Matthew Disney's lab at the Scripps Research Institute of Florida, including Suzanne Rzuczek, PhD, a 2013 MDF Fund-a-Fellow grant recipient, recently published an article describing a new chemical they designed to inhibit the unhealthy repeat-containing RNA molecule seen in myotonic dystrophy type 2. This project was supported by a postdoctoral fellowship awarded by MDF. The study describes the design of a pair of molecules that seek out the unhealthy repeat RNA and attach to it. When both of the molecules attach near each other on the RNA, they join together and permanently attach to each other, forming a strong inhibitor of the RNA. The authors state that they are "using the cell as a reaction vessel and a disease-causing RNA as a catalyst." By this they mean that only cells that have the large DM2 repeat-containing RNA will create their own chemical to inhibit the negative effects of the DM2 RNA. They were able to show that their chemicals reduced the number of unhealthy RNA clumps found in DM2 cells, and were able to partially reverse the improper processing that normally occurs in those with DM2 as a result of the unhealthy RNA.

Click here to read the full article. You can also view a presentation from the 2014 MDF Annual Conference by Dr. Rzuczek where she discusses this research.

09/25/2014

A team of researchers at the University of Illinois at Urbana-Champaign recently published the results of a study in which they designed small molecules to combat myotonic dystrophy type 2 (DM2). Dr. Katharine Hagerman, Research Associate at Stanford University Neuromuscular Division and Clinics, provided MDF with the summary below. The study was published in ChemMedChem. 

Previous studies have suggested that the main problem in the cells of people with DM2 is an expansion of a CCTG DNA repeat sequence in the ZNF9 gene. This DNA mutation is transcribed into RNA, where it forms abnormal structures that pull other proteins into clumps and prevent them from performing their normal activities.

In this study, researchers redesigned a small molecule that disrupted the improper interaction of repeat-containing RNA with other proteins, but was highly toxic to cells. Their new molecule still disrupted the desired RNA-protein interaction, but was less toxic and was able to enter cells with greater ease.

Future studies will take the small molecules and test them in fruit flies and mice to see if the molecules will be safe in organisms while continuing to disrupt the RNA-protein interaction associated with DM2. Click here to access the abstract and article.

07/23/2014

A recently released study identifies the gene that may be responsible for increased side effects in DM2 patients taking statins to lower cholesterol. Katharine Hagerman, PhD, Research Associate at Stanford University Neuromuscular Division and Clinics, provides MDF with a summary of the study conducted at the University of Helsinki in Finland.

Abnormal Splicing of NEDD4 in Myotonic Dystrophy Type 2: A Possible Link to Statin Adverse Reactions
Screen M, Jonson PH, Raheem O, Palmio J, Laaksonen R, Lehtimäki T, Sirito M, Krahe R, Hackman P, Udd B.(June 4, 2014).
American Journal of Pathology. e-publication ahead of printing.

A research study headed by Dr. Bjarne Udd at the University of Helsinki recently described biological pathways affected in both myotonic dystrophy type 2 (DM2) and hyperlipidemia (a medical condition most often characterized by high cholesterol or high triglycerides). Previous studies have shown that 63 percent of people with DM2 have high cholesterol, as well as 41 percent of people with DM1. Statins, a class of drugs used to lower cholesterol levels, are commonly prescribed to treat hyperlipidemia, elevated levels of lipid proteins in the blood, as they can block the action of a liver chemical that helps create cholesterol.

One of the side effects of statins is the development of myopathy, including muscle pain, weakness, and cramping. Approximately 5-10 percent of individuals taking statins can develop these symptoms. Individuals with DM have an increased incidence of myopathic side effects when taking statins, and there are many documented cases where statin-induced myopathy is the first muscle symptom experienced in adults eventually diagnosed with DM2.

In order to identify biological pathways that may be affected by both DM2 and statin therapies, these researchers looked at genes that were regulated differently in healthy muscles compared to DM2 muscles and statin-treated muscle cells. They identified a gene, NEDD4, that had increased expression in DM2 (and DM1), and decreased expression in statin-treated individuals with no muscle condition. Furthermore, they showed that the NEDD4 gene was processed differently in DM2 muscles, and made a few different forms of the protein that weren't seen in healthy muscles. The authors suggest that biological pathways involving NEDD4 may be altered in DM, and may be associated with increased statin side effects. According to DM2 research reviews, statins do not have to be avoided. However, if statin treatment produces or amplifies muscle symptoms, there may be other drugs available to combat hyperlipidemia that do not have these side effects in individuals with DM.

07/01/2014

Interesting Findings Reported in Recent DM Research Studies on Sleep Disturbances

Dr. Katharine Hagerman, Research Associate at Stanford University Neuromuscular Division and Clinics, provides a summary of a recent DM2 sleep survey that has drawn criticism from international DM experts in Italy.

Restless Legs Syndrome and Daytime Sleepiness are Prominent in Myotonic Dystrophy Type 2
EM Lam et al; 2013, Neurology 81(2):157-64

A recent study headed by Dr. Margherita Milone from the Mayo Clinic in Minnesota outlining sleep disturbances in those with myotonic dystrophy type 2 (DM2) has drawn criticism from a group of international experts in Italy headed by Dr. Gabriella Silvestri.

Dr. Milone’s study examined the frequency of sleep disturbances by analyzing surveys filled out by 30 people with DM2, and 43 unaffected individuals. Her study found that those with DM2 had more clinically significant reports of daytime sleepiness, fatigue, altered sleep quality, and restless leg syndrome. Surprisingly, the study also found that obstructive sleep apnea was not a frequent sleep disturbance in DM2, going against previous small studies by Dr. Silvestri and others that estimated the prevalence of obstructive sleep apnea to be between 60% and 67% in DM2. 

Though Dr. Milone’s study was able to assess a larger number of affected individuals than other studies, Dr. Silvestri pointed out that it relied on paper-based surveys instead of more reliable clinical measurements from sleep monitoring.  Overall, studies on sleep disturbance in DM2 highlight the need for overnight and daytime sleep studies when individuals have symptoms that may stem from sleep issues, preferably performed in a sleep clinic that is able to differentiate between obstructive and central sleep apnea, along with assessing for sleepiness, fatigue, other forms of hypoventilation, periodic limb movements of sleep, restless leg syndrome, and REM sleep abnormalities.  

For the article abstract click here. 

Interesting Findings Reported in Recent DM Research Studies on Facial Recognition

A recently published study from Sweden reported impaired facial recognition in people with DM1, and indicated that there are brain differences that affect how faces are perceived and stored by people with DM1. Dr. Katharine Hagerman, Research Associate at Stanford University Neuromuscular Division and Clinics, provides a summary of the Swedish facial recognition study.

Facial Memory Deficits in Myotonic Dystrophy Type 1
J Lundin Kleberg, C Lindberg, and S Winblad (2014) Acta Neruol Scand

Three Swedish researchers recently assessed cognitive differences seen in people with type 1 myotonic dystrophy (DM1). Their previous studies had shown that people with DM1 had a reduced ability to recognize facial emotions, and this correlated with lower sociability. In order to further assess factors affecting sociability in DM1, participants were given pictures of 15 different faces, and were later asked to pick out which faces they had seen before from a set of 30 pictures. Overall, 36% of participants with DM1 had impaired memory of faces, compared to 13% of participants without DM1.

Those with DM1 who had impaired memory of faces tended to falsely recognize faces (false positives), and upon further cognitive testing this group had reduced performance in tests of spatial coordination and motor skills. The researchers believe the impaired facial recognition seen in some people with DM1 indicates deficits in how the information about faces is perceived and stored. They suggest future studies should use eye-tracking to see how people with DM scan pictures to store information. They also recommended conducting MRI studies to see how the brain may differ both in structure and function in those with DM.

For the article abstract click here.  

Myotonic community members often contact the Foundation with questions about genetic testing. Their questions range from how to find facilities that conduct genetic testing for myotonic dystrophy (DM) types 1 and 2 to whether or not they should be tested and how to assess the benefits and risks of having a genetic test.

The question of whether or not to be tested is best answered in partnership with a physician or genetic counselor who understands your family history, your personal circumstances and reasons for exploring genetic testing. Implications associated with DM genetic testing are financial as well as emotional. For this reason, the question of whether to get genetic testing for DM should be considered carefully.

We spoke with Carly Siskind, MS, LCGC, senior genetic counselor on the Stanford University Neuromuscular Disorders Team about the pros and cons of testing and the impact it can have on issues such as insurability.

What do you do as a genetic counselor?

Usually people are referred to me by a specialist such as a neurologist. Sometimes individuals call my office directly. My job is two-fold: to provide basic information about genetics and the implications of testing, and to be the person between the doctor and the patient to help interpret “doctor speak.”

I’d like to emphasize that while genetic testing can provide definitive answers with regard to the presence of disorders like DM, the decision of whether to pursue genetic testing is a personal one with significant potential impacts, both positive and negative. I encourage anyone considering genetic testing to consult with his or her physician or qualified medical professional first, and to consider working with a genetic counselor; we can be helpful in navigating this process.

Do most people understand how DM gets passed along?

Most people I’ve met with to discuss myotonic dystrophy are already fairly well educated on the topic, but I find it helpful to go through some of the basics nonetheless. DM is a complicated disease; for instance, if someone has not inherited the CTG (DM1) or CCTG (DM2) repeat expansion and both copies of this gene—one from each parent—are in the normal range, then he or she won’t develop DM or pass it on to future generations. Only if someone has the expansion will that person potentially experience symptoms or risk passing DM on to his or her children.

What are some of the pros and cons of genetic testing for DM?

If a person isn’t experiencing any DM symptoms but has a family history of DM, it is important to consider the consequences of being tested. Insurability is probably the biggest concern. Even if someone doesn’t have symptoms or a DM diagnosis, if his or her genetics indicate that there is potential to develop DM in the future, it can—and probably will—impact that person’s ability to secure life, disability and long term care insurance. While it is sometimes possible to get this insurance with a family history of DM, it is nearly impossible to get it with a diagnosis, and a diagnosis might still delay access to health insurance.

Because of this, we generally recommend that people think about setting up insurance policies prior to being tested in case their test comes back positive. Unlike health insurance, there’s no federal protection against discrimination for these other three types of insurance.

What are some of the reasons to consider getting tested?

Having a genetic test for DM provides information that, should the test result be positive, can assist the attending physician in anticipating complications, and can also allow for easier insurance approval for other diagnostic testing such as an EKG to detect arrhythmia, a common issue for those with DM. While clinicians typically use the repeat number to help inform diagnosis and care considerations, I have found that people in the community like to use this number as a way to help tell their personal stories and create connections to others living with DM.

Is the DM genetic test widely available? Where can people find a lab if they want to be tested?

There are a number of labs that conduct testing for DM, including academic or institutional settings such as Baylor College of Medicine, etc., and for-profit corporations such as Athena Diagnostics and Medical Neurogenetics. There are a number of labs in the U.S. that offer testing for DM. Prices can vary considerably depending on the lab and whether someone is being tested for DM1 or DM2. I would advise people to do their research in advance, and call their insurance plan before testing to see if the insurance company will cover a particular lab.

Insurance plans may request a CPT code to consider a request for genetic test reimbursement. CPT stands for Current Procedural Terminology and is generated by the American Medical Association for coding, billing and insurance purposes. CPT codes can be found on each lab’s website and are publically available.

The insurance company may also want an ICD-9 code, which is a diagnosis code used by the US Centers for Disease Control (CDC) and other international public health agencies to assist with disease reporting. ICD stands for International Classification of Diseases. The current diagnostic code for myotonic dystrophy is 359.21. Updated ICD-10 codes will be implemented in October 2014 and at that time the DM code will change to G71.1.

Insurance companies should be able to explain what percentage of the cost of a DM genetic test they will cover. Individuals with very low incomes can sometimes qualify for financial assistance programs.

What does the testing involve?

It requires a blood draw. It takes about three weeks to get the results, although timing varies from lab to lab. For those with DM in their family who choose not to get the genetic test, I recommend talking with their doctor about scheduling an EKG every year or two, at least until they’re 18 years old. While an abnormal EKG may not imply a DM diagnosis, when coupled with a family history of DM, an abnormal EKG should direct the physician to conduct additional follow up testing.

What do you discuss with individuals who have a family history of DM and are considering getting pregnant?

Reproductive options are definitely an issue we discuss when appropriate. The risk of having a child born with DM is 50/50 for each pregnancy. In this situation, prospective parents can think about options for testing the pregnancy. Tests can be run to look for the repeat expansion at 10-12 weeks of pregnancy through chorionic villus sampling (CVS) or by amniocentesis after 15 weeks.

It’s important to note that the expansions can grow and change as the baby develops. The number of repeat expansions found by CVS or amnio are not necessarily going to be the same number that the baby has when it is born, so those numbers can be used to determine whether the baby will be affected by DM, but not to predict disease severity. The implication for this type of testing would be that the parents can decide if they want to proceed with the pregnancy.

For those who don’t want to go that route, there’s also the option of pursuing in vitro fertilization (IVF) and getting the appropriate testing done before implantation to ensure the DM genetic mutation has not been passed along to the baby. This pre-implantation genetic diagnosis (PGD) test is done after the sperm and egg are fertilized and have developed up to eight cells. At that point, one or two of those cells are removed and tested for the DM repeat expansion. Doctors can then transfer to the mother only embryos that don’t have the expansion, so the disease won’t be passed on.

Generally, it can be assumed that about 50% of these fertilized eggs have the expansion. IVF/PGD is a very expensive option, usually costing at least $20,000 per cycle so, depending on state and insurance plan, prospective parents may or may not be able to get some help with these costs.

Note: Athena Diagnostics offers qualifying patients a substantial discount on its regular price for clinical laboratory services. If you cannot afford to pay for testing ordered from Athena, you may obtain a 75% discount off the list price if you meet certain income guidelines. For more information, see call (800) 394-4493 and ask to speak with a Reimbursement Services Representative.

03/18/2014

Researchers at important academic labs around the US have recently published exciting new information about advances in DM research. The Matthew Disney Lab at The Scripps Research Institute in Florida announced the results of a study examining RNA toxicity in DM2 patients. Summaries of the studies and results are below, along with links to the PubMed abstracts and complete research publications.

Structure of the Myotonic Dystrophy Type 2 RNA and Designed Small Molecules that Reduce Toxicity Childs-Disney et al (Matthew Disney Lab)

Researchers at Scripps Research Institute in Florida recently examined the structure of the toxic RNA molecule made from the DNA mutation causing myotonic dystrophy type 2 (DM2). Dr. Matthew Disney and his colleagues used a technique called X-ray crystallography to look at the shape of the RNA at the atomic level in order to determine what types of drugs would best attach to it and reduce its toxicity.  

One of the reasons the DM2 RNA is unhealthy in cells is because it changes how other genes are processed and regulated. They showed that their custom-designed drugs were able to reverse the improper processing of a gene known to be affected in DM by varying degrees depending on the design of the drug. This study shows that drugs they previously proposed could bind the toxic RNA are now able to be administered to cells with toxic RNA similar to DM2 and reduce the RNA toxicity.

For more information:

Click here to view a pdf of the full article

Click here to read the abstract

01/22/2014

To support our commitment to research, MDF awards fellowship grants to postdoctoral researchers as part of our annual Fund-A-Fellow (FAF) program. We recently caught up with one of our current grant recipients, Dr. Nicholas Johnson, Assistant Professor of Neurology at the University of Utah.

Dr. Johnson was inspired to focus his practice and research on myotonic dystrophy after working for five years at the University of Rochester with Dr. Chad Heatwole, Dr. Richard Moxley, Dr. Charles Thornton and a number of other clinicians and researchers leading the charge to find new treatments and cure for DM. He opened his practice at the University of Utah in July of 2013 and is excited to be able to treat the large DM population in Utah and surrounding states.

“There is an excellent neurology department at the University of Utah,” Dr. Johnson says, “but previously no one was focused specifically on researching DM. Being here gives me the opportunity not only to provide ongoing treatment to those individuals, but to include many of them in our research studies as well, which is exciting.”

We spoke with Dr. Johnson about his current FAF research.

MDF: First, tell us about the research you’ve been doing as a result of receiving the FAF grant.

NJ: “Sure. Once I received the FAFA grant, I began a project in March 2012 to develop a tool that can be used in a clinic or in research studies to measure how myotonic dystrophy impacts the quality of life of a child with congenital or childhood-onset DM. 

“The tool is called Congenital and Childhood Myotonic Dystrophy Health Index or CCMDHI. It’s a survey-based tool that collects data about quality of life from birth to age 18. Until now, there’s been very little data about how DM progresses from birth to adulthood, but that information is necessary for clinical trials to move forward.”

MDF: Can you tell us about the survey and what you’ve discovered in the two years that you’ve been conducting research? 

NJ: “We interviewed 32 children and 12 parents and created the survey with their direct quotes so we could compare how their symptoms might impact the larger DM population’s quality of life. The survey was then sent out via the Myotonic Dystrophy Family Registry, the National Registry for DM and FSHD at Rochester, and the Canadian Neuromuscular Disease Registry, as well as via Dr. Anne-Berit Ekstrom of Sweden, who takes care of a large population of Swedish patients with congenital or childhood DM.

“One of the salient discoveries was that there was more than expected cardiac issues reported in children when we asked parents about comorbidities. Another interesting result was that 20-30% reported ADHD or autism symptoms.

“Of children over 18 years old, 86% were unemployed, which is pretty significant and tells us that there are a lot of ongoing issues and we need to emphasize social support when we take care of these patients.  Communication problems are a huge issue. Reports of fatigue and difficulty with mobility were also reported.

“Importantly, reported symptoms seemed to vary between birth and age 18 and over. Issues for those with young children were very different from those with older teenage children. And all children were very different from the experience of adult onset DM. Parents reported significantly more communication problems, as well as emotional and social issues. On the upside, there were less myotonia and pain symptoms in the children.”

MDF: What happens next?

NJ: “Now that we have a preliminary instrument, we’re finishing testing and will be moving on to our next study. I’ll be working with a research team here at the University of Utah on a study called ‘Health Endpoints and Longitudinal Progression in Congenital Myotonic Dystrophy’ or HELP CDM.

“This study, which is funded by MDA, is expected to start in January 2014 and will validate CCMDHI while helping find other endpoints that will be important in clinical trials.

“During the study, children from birth to 13 years old will come in for a variety of testing, including strength and functional testing, speech and swallow testing, neuropsychological testing, and respiratory and cardiac testing. Sixty children with congenital DM, who are currently being treated here at the University of Utah and also at and University of Western Ontario, will be measured. Ultimately, we hope this will allow us to transition to successful trials and therapies for the pediatric population.

“Separately, we’ve partnered with MDF to send out a survey via the Myotonic Dystrophy Family Registry to see how women with DM are affected during pregnancy and whether symptoms improve or worsen. That survey will be going out soon. Previously, researchers have looked at complications that can occur during pregnancy but not how quality of life is impacted as a result.”

MDF: You’ve mentioned the national DM registries a few times. Can you speak to why it’s important to join these registries?

NJ: “The Myotonic Dystrophy Family Registry established by MDF and the National Registry for Myotonic Dystrophy at the University of Rochester have been instrumental in recruiting patients for our upcoming HELP CDM study. I mentioned that we’re also using these registries to conduct a number of surveys that will provide us with data we need to keep research moving forward. I encourage everyone to sign up, if they haven’t already. It really does make a difference.”

12/18/2013

Researchers from the University of Rochester recently summarized the “diagnostic odyssey” experienced by a group of 814 individuals with myotonic dystrophy enrolled in their national registry.  They focused on individuals with a confirmed diagnosis and with first symptoms starting after more than 4 weeks of age, and collected the age when the first symptom was observed, the type of symptom first experienced, any misdiagnoses, the age when a correct diagnosis was made, and the diagnostic tests administered.

This study found that members with myotonic dystrophy type 1 (DM1) experienced an average of 7 years delay to diagnosis, and members with myotonic dystrophy type 2 (DM2) had an even more stunning delay of 14 years to get a correct diagnosis.  On average, DM1 individuals experienced their first symptoms at age 26, whereas DM2 individuals had a later average age of onset at 34 years old.  In general, one quarter of the study’s myotonic dystrophy population experienced their first symptom before the age of 18.

Researchers determined that the type of symptom that manifests first can help dictate how quickly it will take for a correct diagnosis for DM1.  In DM1, members who reported weakness as their first symptom waited on average 6.6 years for their diagnosis, whereas a significantly longer delay in diagnosis was found when the first symptom was myotonia (7.6 years), fatigue (11.5 years), and sleep disturbance (15.6 years).  In DM2, a proper diagnosis was delayed on average 7 years, and was not significantly changed based on the type of symptom first observed.  The most common first symptom in DM1 was grip myotonia, followed by arm weakness, general weakness and leg weakness.  The most common first symptom in DM2 was leg weakness, followed by grip myotonia, general weakness and arm weakness.

Given that members with DM2 waited much longer for a correct diagnosis, the researchers further examined what caused the delay.  One quarter of DM2 members had an incorrect diagnosis, most often originating from a neurologist.  The most common misdiagnosis was limb-girdle muscular dystrophy, but others included chronic fatigue, fibromyalgia, arthritis, and multiple sclerosis.  DM2 members also underwent significantly more testing than DM1 members, having more EMGs, muscle biopsies and genetic testing.  Overall, 71% of DM2 members in this study had a confirmed genetic diagnosis, compared to 58% of DM1 members.

The authors stressed the need for a timely diagnosis to facilitate addressing the short term medical needs of people with DM, because many of the symptoms are disabling and reduce quality of life.  They also note that it is “imperative to diagnose patients earlier in the disease course if promising experimental therapies can reverse or delay onset of symptoms and potentially ward off the progression of many disabling manifestations”.  Now that genetic diagnoses have been available for DM1 and DM2 since 1992 and 2001, respectively, and much effort is being put into educating the community and medical trainees about DM, hopefully the diagnostic odyssey for people with DM will be improved.

An abstract of the original article can be found here.

08/22/2013

Maurice Swanson, Ph.D., Professor of Molecular Genetics and Microbiology at University of Florida, Gainesville, and a team of researchers have found that the muscleblind-like 2 (MBNL2) protein in the central nervous system (CNS) may be responsible for the neurological impacts of myotonic dystrophy (DM), providing hope for new treatments. Muscleblind is a type of protein that plays an important role in switching proteins typically found only in babies to proteins found in adults. If this switch isn’t made, an imbalance exists that leads to myotonic dystrophy.

Dr. Swanson states that the team’s work seeks to understand what causes myotonic dystrophy beyond the mutations in the DM1 and DM2 genes.

Dr. Swanson examined which genes were affected by loss of MBNL2 in the brain and found more than 800 affected genes. Many of them had one thing in common: the encoded protein could be made in both fetal and adult forms and MBNL2 appeared to regulate which version was created, according to an article in Neurology Today. One persistent concern that people living with DM1 and DM2 have is the effects of this disease on the brain. “People who don’t have DM usually feel refreshed after a night’s sleep. Myotonic dystrophy patients do not routinely achieve a normal sleep pattern; instead, they have an interrupted series of sleep-wake patterns that do not allow for deep, restful sleep cycles”.

Dr. Swanson created a mouse that lacks the MBNL2 protein as an animal model for DM effects on the CNS. These mice showed normal skeletal muscle structure and function. However, the mice did have DM-related sleep issues, such as a higher number of REM sleep episodes and more REM sleep in general, leading to less restful sleep. In mice lacking MBNL1, another member of the MBNL protein family, the skeletal muscle effects were similar to what is seen in DM. But the central nervous system was not affected, according to Dr. Swanson. 

“What we would like to do now is identify the specific cellular events that are abnormal in the DM brain and see if there is something we can do to treat these disease manifestations with focused therapy development. We would also like to understand the heart and muscle problems in DM. We have developed mice with DM-associated problems and we want to use these mouse models to develop effective drug treatments. Also, we want to understand what is so different about the congenital form of DM. Why does it manifest in babies and children? If we can develop animal models for congenital DM, then we can begin to address the important question of what goes wrong during fetal life,” explains Dr. Swanson.

Recently, therapy development for DM has accelerated and treatments based on anti-sense oligonucleotides will hopefully enter clinical trials in the near future. These new studies focused on the roles of MBNL proteins in CNS function should lead to alternative therapeutic strategies designed to reverse effects caused by expression of the mutant DM1 and DM2 genes.

04/16/2013