Researchers discover new muscular dystrophy gene (1/31/2008)

Researchers at the University of Toronto and the Medical University of Graz have discovered a new form of muscular dystrophy (MD), which may lead to better diagnosis and treatment for people living with unidentified muscles diseases.

This new form of MD, called X-linked myopathy with postural muscle atrophy (XMPMA), is caused by a mutation in the four-and-a half LIM domain 1 gene (FHL1). Scientists predict that this gene affects the protein function as well as the protein level in muscle cells. This is the first FHL protein to be linked with a human genetic disorder and further supports the role of FHL proteins in the development and maintenance of muscle tissue.

The discovery was made at the Centre for Addiction and Mental Health (CAMH) by Professor John Vincent from the Department of Psychiatry, who is also a scientist at the Centre for Addiction and Mental Health, and Dr. Christian Windpassinger, a post-doctoral fellow at CAMH who is an assistant professor at the Medical University of Graz, Austria, in collaboration with an international team of researchers.

Their discovery provides hope of better treatment and diagnosis because it may give people living with an unidentified muscle disorder a diagnosis for their illness, and potentially lead to genetic screening for this type of MD.

XMPMA is characterized by the following:

• An athletic appearance during early stages of the disease, yet detailed examination reveals weakness and deterioration of muscles that affect postur
  
  
• A limited range of neck movement
  
  
• Abnormal protrusion of the shoulder blade
  
  
• Curved spine, back pain and gait problems

Unlike more severe forms of muscular dystrophy such as Duchenne's, symptoms of XMPMA were not noticed until affected individuals were approximately 30 years old.

Vincent and Windpassinger analysed the data at CAMH and identified the gene responsible for this type of MD. The finding was published in the American Journal of Human Genetics.

"By studying several large multigenerational families affected with this previously unspecified X-linked recessive form of MD, we identified mutations within the gene FHL1; the gene is located on the X chromosome and female carriers of the mutation in FHL1 have a 50 per cent chance of passing on the disease to their male children," said Vincent.

According to Vincent, this gene discovery may have important implications for clinicians. Doctors should consider screening for mutations in the FHL1 gene for individuals living with unidentified muscle diseases including diseases of the heart muscle.

Muscular dystrophy is the name of a group of muscle disorders characterized by progressive weakness and wasting of muscles that control body movement. It affects tens of thousands of Canadians and there are few treatments.

Note: This story has been adapted from a news release issued by the University of Toronto

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