Muscular Dystrophy Heavily Affecting US Latino Males

Duchenne/Becker (DBMD) and Facioscapulohumeral muscular dystrophies are a part of a group of more than 30 genetic diseases that cause progressive weakness and loss of muscular mass. Recent reports show that prevalence of muscular dystrophy is higher among Hispanic individuals than non-Hispanic white or black individuals. However, there have been a series of research developments that could lead to future therapies for the currently untreatable disease.

The genetic muscle-weakening disorder DBMD affects 1 in 5,600 to 7,700 males (5 through 24 years of age) in the United States, and a recently published report, printed in the journal "Pediatrics," revealed that prevalence rates for DBMD is highest among Latinos.

DBMD primarily affect boys (between ages 7 and 13), robbing them of their ability to walk and lead to an early death. While the reported documented more cases of MD among non-Hispanic whites (reflecting the sizable proportion of non-Hispanic white individuals in the MD STARnet), it showed that prevalence rates were highest among Hispanics (1.50 per 10,000 compared to 1.45 per 10,000 for non-Hispanic white).

According to the report, increased prevalence among Hispanic individuals may reflect suspected underreporting in census estimates for Hispanic children, ages 5-9, or it could reflect racial and ethnic differences in time of diagnosis and access to care.

The identification of the novel gene, Smchd1, has exposed the gene's involvement in the development of facioscapulohumeral muscular dystrophy. Researchers at the Walter and Eliza Hall Institute in Australia piloted research that established that Smchd1 is involved in DNA management and X chromosome inactivation. According to the report, the gene is dysfunctional in patients with FSHD2, a rare form of facioscapulohumeral muscular dystrophy (FSHD), which is a disorder that affects the skeletal muscles of the face, shoulders and upper arms.

Smchd1 is very unusual in its interactions with the genome and encodes an epigenetic factor that can switch genes off to suppress their function. The 'Goliath' molecule "very delicately squeezes itself into a tiny 'seat' on the DNA. It binds at just a few discrete sites on the DNA, and then draws these pieces together to 'shield' them from being activated," said researchers from Walter and Eliza Hall Institute.

The critical discovery of the gene allows for the deeper research into genetic changes, mutation and its effect on functions. In the long term, Smchd1 researchers could develop drugs that act as a substitute during mutation activity and prevents debilitating muscle wasting.

To revisit the subject of developing a drug to treat muscular dystrophy, a pioneering treatment has been developed to eliminate the severe muscle-wasting condition known as Duchenne muscular dystrophy. However, the drug has been turned down for early NHS funding.

European Medicines Agency (EMA) approved Translarna during August 2014, and it became the first drug to address the cause of Duchenne muscular dystrophy, which is a progressive genetic disorder characterized by muscle erosion and weakness, is caused by an absence of dystrophin, a protein that helps to keep muscle cells intact. While Translarna is available in many EU nations, it isn't available in England and several other nations around the world. The drug could help to slow muscle progression and help children to walk longer.

Following NHS England's rejection, the National Institute for Health and Care Excellence (NICE) plans to conduct a drug review on Translarna, and they will report back in early 2016. During December 2014, Translarna was granted orphan drug designation (ODD) status in the U.S. and Europe for the Treatment of mucopolysaccharidosis.

"It is very disappointing for the Duchenne muscular dystrophy community that the NHS has decided not to fund Translarna at this juncture. The drug is already available in several European countries following EMA conditional approval last year including Germany, Greece, Italy and France," said professor Kate Bushby from the The John Walton Muscular Dystrophy Research Centre and lead for that clinical trial of Translarna Drugs, in a recent news release. "Drugs for rare diseases are very expensive, but this is a function of the development pipeline and should not disadvantage the patients who suffer from these conditions.

"If we are to have a constructive pipeline for rare disease drug development, then there needs to be a way to ensure that drugs which have been approved by the EMA have a mechanism to be available on the NHS."

Bushby continued to state that it was disheartening to see investments from the research community and time from patients and families go to waste after they've participated in studies.

Robert Meadowcroft, chief executive of Muscular Dystrophy U.K., said in a news release, "This news is a harsh blow to each and every boy and young man living with Duchenne muscular dystrophy. ... Parents of young children have faced a grueling nine-month wait for an answer on funding, only to hear 'no' from NHS England. ... Our focus now is to support parents affected by this decision through the waiting period, and to explore all alternatives, including working with senior doctors on requests for individual funding."

When it comes to the prevalence of Duchenne and muscular dystrophy in the U.S., rates are highest for Hispanic individuals and lowest for non-Hispanic black individuals. Also, concerning estimates for disease development in relation to age, Hispanic individuals exceeded non-Hispanic white individuals for all but the youngest age group. Additionally, when prevalence rates managed to decrease, rates for Latinos still exceed rates for other racial and ethnic groups.

Researchers are unclear as to why Latino males are heavily impacted by the disease, but the new study could heighten awareness about disease prevalence and understanding about the role the disease can play in the lives of young men.