domingo, 23 de febrero de 2014

Muscular Dystrophy, Genetics & Public Health Research

CDC’s New Muscular Dystrophy Research | CDC Features

Muscular Dystrophy, Genetics & Public Health Research

CDC’s Muscular Dystrophy Surveillance Tracking and Research Network is the only population-based muscular dystrophy tracking program in the United States

CDC Muscular Dystrophy Home Page: Muscular Dystrophies are a group of genetic disorders that result in muscle weakness and a decrease in muscle mass over time

CDC article: Duchenne Muscular Dystrophy clinical care guidelines (2010)

[PDF - 664KB].

CDC’s New Muscular Dystrophy Research

Public health research of muscular dystrophy

Muscular dystrophy is medically complex, often requiring care from multiple specialists. These specialists may be affiliated with a muscular dystrophy specialty clinic. Research data is often collected at these clinics since they treat a large number of individuals with muscular dystrophy. However, using clinic data from only large clinics leaves out those with muscular dystrophy who don't receive care at one of these specialty clinics. Population-based public health tracking of rare conditions like muscular dystrophy can answer questions that are difficult to address with information collected only from specialty clinics. Population-based tracking captures a picture of those with muscular dystrophy who receive medical care in a variety of environments within a specific geographic area.

CDC's MD STARnet (Muscular Dystrophy Surveillance Tracking and Research Network) is the only population-based muscular dystrophy tracking program in the United States. Data from the five participating MD STARnet locations document:

How common each type of muscular dystrophy is in the population.
How long it takes for a diagnosis to be made, diagnostic tests received, and age at confirmation of diagnosis.
Types of medical services, medications, surgeries, and therapies received.
Types of clinics and healthcare professionals who care for people with muscular dystrophy.
How services and treatments affect outcomes and quality of life.
The progression of the disease.
Impact of the disease on families and caregivers.

Recent findings

Two recent scientific papers from the MD STARnet program present new research information on muscular dystrophy.

Patterns of Growth in Ambulatory Males with Duchenne Muscular Dystrophy

Physicians, nurses and other clinicians rely on growth reference standards (growth charts) to assess development. This paper includes the first growth charts developed for boys with Duchenne muscular dystrophy who have not taken steroids and can still ambulate (walk) at ages 2-12 years. This paper also compared these boys with Duchenne muscular dystrophy to the 2000 CDC growth charts for all boys. Key findings are:

Boys with Duchenne muscular dystrophy tend to be at the extremes of weight and body mass index compared with boys in the general pediatric population in the United States.1
In height-for-age comparison, boys with Duchenne muscular dystrophy are shorter than the general population of boys in the United States, and average height is consistently lower from an early age.1
In BMI-for-age comparison, the average BMI is higher among boys with Duchenne muscular dystrophy than in the U.S. general population of boys.1

This new information will help clinicians track growth and detect unusual patterns in their patients with Duchenne muscular dystrophy.

Sibling Concordance for Clinical Features of Duchenne and Becker Muscular Dystrophies

For families with more than one son with Duchenne or Becker muscular dystrophy, parents and healthcare professionals have been eager to learn whether the disease course (progression of the disease over time) in one son can predict the disease course in another. A recent research study has addressed this question:

According to the study, "the time to ceased ambulation [no longer able to walk] for older brothers predicts the time to ceased ambulation for their younger brothers." Use of steroids was not found to impact these results, however this study included only a small number of sibling pairs in which one or both of the brothers used steroids.2
For each additional month of ambulation by the older boy, the likelihood of ceased ambulation by the younger boy decreased by 4%.2
Sibling concordance (similarity in the ages at which medical problems occurred) was not found in the development of scoliosis (curvature of the spine) and cardiomyopathy (enlargement of the heart). Difference in treatments, other medical conditions such as obesity, the presence of other genes, and factors at the cellular level may explain the lack of correlation.2

These findings may help healthcare professionals offer guidance and counseling to families with multiple sons who have Duchenne or Becker muscular dystrophy. Additionally, future research may focus on identifying which genes affect the course of the condition in siblings.

Upcoming research

In the next few years MD STARnet research will address how common Duchenne and Becker muscular dystrophy are by race and ethnicity, followed by how common the other forms of muscular dystrophy are in the United States. Currently, there are no accurate data on how common most muscular dystrophies are in this country.

Data captured in MD STARnet will also be used to evaluate the Duchenne muscular dystrophy clinical care guidelines published in 2010

[PDF - 664KB]. This evaluation will address how frequently healthcare professionals are using recommendations in eight different areas of care, and how closely these recommendations are being followed.

In the future

Experts in the field suggest that promising clinical trials may eventually lead to newborn screening for Duchenne muscular dystrophy. Scientists are developing the infrastructure and evidence to screen for Duchenne muscular dystrophy and follow newborns once they are diagnosed. Once newborn screening is approved and implemented, the MD STARnetinfrastructure could be used to monitor newborns with Duchenne muscular dystrophy, and track early treatment services.

Muscular dystrophy has a tremendous impact on affected individuals, families, health systems, and communities. Future research studies have a role in improving care for individuals and families.

More Information

References

Patterns of Growth in Ambulatory Males with Duchenne Muscular Dystrophy
West NA, Yang ML, Weitzenkamp DA, Andrews J, Meaney FJ, Oleszek J, Miller LA, Matthews D, Diguiseppi C. J Pediatr. 2013; 163(6):1759-1763.
Sibling Concordance for Clinical Features of Duchenne and Becker Muscular Dystrophies
Pettygrove S, Lu Z, Andrews JG, Meaney FJ, Sheehan DW, Price ET, Fox DJ, Pandya S, Ouyang L, Apkon SD, Powis Z, Cunniff C. Muscle Nerve. 2013 Sep 13. [Epub ahead of print]

Muscular Dystrophy: Kevin’s Story

There are nine major types of muscular dystrophy. These disorders differ in the muscles they affect, the age when signs are first seen, and the genes that cause the disorder.

Kevin’s Story

Kevin was 28 when he was diagnosed with has facioscapulohumeral muscular dystrophy, or FSHD. “I don’t want my identity to be my muscular dystrophy. I don’t want people to think I sit at home and can’t do anything. I don’t ever want to have a day where I don’t have lots to do.”

Leading an active life with muscular dystrophy has its challenges, but Kevin takes them all in stride. There was the frustration this former distance swimmer and three-time Junior Olympian felt when he couldn’t swim 25 yards. And the time he was headed to a black tie dinner only to cancel his plans when he learned that one of the two wheelchair cabs in town was broken. “That was a real ah-ha moment. I don’t want to be in that position again…the position of not being able to do something because of my limited mobility.”

Kevin was living in Washington, DC when he was diagnosed with FSHD. As the muscle inflammation, wasting, and loss of balance got worse, his doctor suggested he move someplace warmer that had FSHD specialists. Kevin chose Atlanta. “I took a big pay cut. I was looking for a less stressful job with really good insurance. My new company offered long term disability insurance from day one. I was thinking long term without making it sound like I was thinking long term.”

“Stairs were tough, but I could do them. Then I decided to use the cane, and then the crutch. I had six trips to the ER during the first two and a half months of the year, all from falls. My doctor said next time it would be a broken hip, and I’d be in the hospital for months. That’s when I got the wheelchair. Now I can do so much more.”

Earlier this year Kevin decided to go on disability. Volunteer work keeps him busy, and his physical and mental health has improved. He works with the Humane Society and helps lead a fundraiser supporting AIDS vaccine development. He’s registering to be a citizen lobbyist during the next Georgia legislative session. Kevin also has an idea to help others with FSHD. “We need something to help people when they’re first diagnosed. New patients ask the same questions. It’s overwhelming to learn you have a disease you can’t even pronounce. Social media is helping connect patients and break down the isolation faced by many with FSHD.”

As Kevin enters his second decade living with muscular dystrophy, he laughs that he turned 40 and got a minivan in the same month. “I don’t think that’s how your midlife crisis is supposed to go.” When asked if he thinks about the next ten years, he says “I can’t go there. I can’t stress about the things I can’t control. Today my life is great.”

CDC would like to thank Kevin for sharing this personal story.

What is muscular dystrophy?

Muscular dystrophies are a group of genetic diseases characterized by progressive weakness and degeneration of the muscles that control movement. Some muscular dystrophies are seen in infancy or childhood, while others may not appear until middle age or later. The disorders differ in the extent of muscle weakness, the rate of progression, and the pattern of inheritance.

Facioscapulohumeral muscular dystrophy is named for the areas in the body that are affected most often: muscles in the face (facio-), around the shoulder blades (scapula-) and in the upper arms (humeral). Weakness in the facial muscles can make it difficult to turn up the corners of the mouth when smiling, drink from a straw, or whistle. Weak shoulder muscles tend to make the shoulder blades “stick out” from the back, and weakness in the shoulders and upper arms can make it difficult to raise the arms overhead. FSHD worsens slowly over decades and can lead to a condition called foot drop which affects walking and increases the risk of falls. Muscle weakness in the hips and pelvis can make it difficult to climb stairs or walk long distances.

There is no specific treatment to prevent or stop muscular dystrophy. Physical and occupational therapy, respiratory therapy, speech therapy, orthopedic appliances, and assistive technology may improve quality of life. Medications can help maintain muscle strength.

What is CDC doing?

The Centers for Disease Control and Prevention (CDC) focuses on improving quality of life and encouraging full participation at every age for those with muscular dystrophy. Through research, we are learning which health care services may be most beneficial for those with the condition, and in collaboration with our partners, we develop tools to assist clinicians treating patients with muscular dystrophy.

CDC is funding the development of clinical guidelines for four types of muscular dystrophy. Working with the American Academy of Neurology (AAN), recommendations are being developed for facioscapulohumeral muscular dystrophy, myotonic dystrophy, limb-girdle muscular dystrophy, and congenital muscular dystrophy. These guidelines will be published for physicians by the AAN in 2013. CDC collaborated with partners to release treatment recommendations for Duchenne muscular dystrophy in 2010.

CDC supports and manages MD STARnet, the Muscular Dystrophy Surveillance, Tracking, and Research Network. MD STARnet is the only program identifying and studying everyone born with Duchenne and Becker muscular dystrophy since 1981 in six states. The information we collect helps us understand health care needs and the quality of life of individuals with muscular dystrophy and their families. Researchers are currently testing the feasibility of collecting information on the seven other muscular dystrophies.