MDA clinic directors and researchers gather
for three days of talks

Nearly 600 conferees gathered at the South Point Hotel in Las Vegas Jan. 26-28, 2009, for the MDA National Clinic Directors’ Conference, where a number of speakers presented research and care updates on Duchenne muscular dystro-

phy, myotonic dystrophy, facioscapulohumeral muscular dystrophy, limb-girdle muscular dystrophy, congenital muscular dystrophy, Friedreich’s ataxia, spinal muscular atrophy, acid maltase deficiency and ALS.

Carsten Bonnemann, an MDA research grantee who co-directs the MDA clinic at Children’s Hospital of Philadelphia, talked about the simi-larities and differences among various types of congenital muscular dystrophy.

Susan Iannaccone, who directs the MDA clinic at Children’s Medical Center of Dallas, emphasized the need for multidisciplinary care for children with spinal muscular atrophy.

Katherine Mathews, who directs the MDA clinic at University of Iowa Hospitals & Clinics in Iowa City, reported early data from the Muscular Dystrophy Surveillance Tracking and Research Network (MD STARnet), a project of the Centers for Disease Contol and Prevention.

John Day, an MDA research grantee who directs the MDA clinic at the University Medical Center-Fairview in Minneapolis, discussed the need for doctors to “recognize the multiple faces of myotonic dystrophy.”

Lamin defects may disrupt
nerve-muscle signals in
Emery-Dreifuss MD

Mutations in the lamin A/C gene on chromosome 1 and the emerin gene on the X chromosome both can cause Emery-Dreifuss muscular dystrophy (EDMD),

but the precise mechanisms by which they do so are still being identified.

Now, a multinational team has found that, in mice with an EDMD-like disease, lamin protein defects interfere with the way cell nuclei normally localize in skele-tal-muscle fibers at the point where each fiber receives signals from a nerve cell.

The researchers say their results “strongly indicate” that defects at the neuromuscular junction (where nerve and muscle connect) contribute to the lamin A/C type of human EDMD, and provide insights into at least one cellular and molecular mechanism operating in this disease.

The team, coordinated by Tom Misteli at the National Cancer Institute of the National Institutes of Health in Bethesda, Md., published its findings Jan. 5, 2009, in the Journal of Cell Biology. Investigators found that the neuromuscular junctions are abnormally organized in these mice and that nerve-to-muscle signals are altered. They say humans with lamin A/C-related EDMD show similar molecular defects in their muscles.

MDA grantee Howard Worman at Columbia University, who has conducted several studies of the molecular consequences of EDMD, cautions that heart-muscle cells, which are severely affected in lamin-related EDMD, do not have neuromuscular junctions, demonstrating that a different disease mechanism exists in these cells.

In October 2008, Worman’s group identified a signaling pathway in the heart called ERK as a mechanism of cardiac damage in lamin A/C-related EDMD. (See Research Updates, January 2009.)