A new study in the journal Pediatrics has found that approximately one in 5,000 young boys in the U.S. have Duchenne or Becker muscular dystrophy, two of the more common inherited neuromuscular disorders.
Duchenne muscular dystrophy (DMD) is a condition found almost exclusively in boys. The hallmark of the disease is muscle weakness, the symptoms of which begin to appear at a young age and progress rapidly leading to significant disability. Boys often end up in a wheelchair by age 9 or 10 because of weakness in their legs. The symptoms eventually spread to other parts of the body, including the heart and muscles responsible for breathing, and the disease can often be fatal by the time the individual reaches his 20s or early 30s.
Becker muscular dystrophy is similar to DMD, but tends to appear later and the progression of symptoms is usually slower and more varied.
The study, which involved a team of researchers including University of Rochester Medical Center neurologist Emma Ciafaloni, M.D., examined medical records and birth and death certificates from 1982 to 2011 in six states: Arizona, Colorado, Georgia, Hawaii, Iowa, and New York. Results were analyzed in five year increments.
The researchers found the disorders in roughly 2 per 10,000 boys between 5 and 9 years old in the 1991-1995, 1996-2000, and 2001-2005 time periods. In 2006-2010, the prevalence was 1.5, but the researchers speculate the lower figure may be the due to delayed diagnosis, among other factors.
Hispanic youth had a higher prevalence in all but the last time period, while African-American children were least likely to be affected for all time periods. DMD was by far the more common of the two, consisting of three-quarters of the 845 total cases included in the study.
The study also included researchers from the University of Iowa, the University of Colorado-Aurora, the University of Arizona, and the New York State Department of Health. The study was funded by the U.S. Centers for Disease Control and Prevention, through the Muscular Dystrophy Surveillance, Research, and Tracking Network.
You can read more about the findings here.