DMD Study Focus Is Pathophysiology of Dilated Cardiomyopathy

This week, a group of interdisciplinary researchers from universities throughout Italy released study findings with potentially important clinical implications for patients with Duchenne muscular dystrophy (DMD). The study, entitled “Genetic Modifiers of Duchenne Muscular Dystrophy and Dilated Cardiomyopathy,” focused on understanding the pathophysiology of dilated cardiomyopathy (DCM), a major complication and leading cause of death for patients with DMD, as well as the possible effects of steroidal treatment. The study was published in the latest edition of the open access journal PLOS One.

The study was conducted in the laboratory of senior investigator Dr. Elena Pegoraro, MD, PhD, Associate Professor of Neuroloy at the Department of Neurosciences, University of Padova. Dr. Pegororaro’s research focuses on utilizing certain laboratory techniques, including mutation identification, cloning, protein detection and quantitation, immunohistochemistry, and genomics, to study congenital muscular dystrophies such as DMD.

Dr. Pegoraro and colleagues utilized DNA samples from 178 DMD patients who met the following criteria:

• confirmed clinical diagnosis of DMD
• records of annual cardiologic follow-up, including 2D-M-mode echocardiography
• availability of a DNA sample

The DNA sample was used to retrospectively assess the specific genotypes of patients who developed DCM, in comparison to their age of onset, and whether they were on steroidal treatment and, if so, which type.

Patients were followed up, on average, until they were 16 years old, in which the primary study finding showed that 71 out of the 178 patients developed DCM, and that glucocorticoid corticosteroid treatment did not have a significant independent effect on DCM onset.

Secondary findings of interest included:

• Loss of ambulation was observed in 163 patients, of whom 145 did not have severe cognitive impairment or other medical conditions that could have contributed, such as bone fractures or prolonged immobilization.
• In 57 patients in whom both DCM onset and loss of ambulation were observed during follow-up, a protective effect on the heart of early loss of ambulation was not observed.

When discussing the importance of these findings, Dr. Pegoraro and her co-authors wrote, “Our data do not confirm effectiveness of steroids in delaying DCM, on the contrary, some ‘outlier’ patients who never developed DCM, or developed it late in life, tended to be more frequently untreated. This may reflect detrimental effects of steroids on the myocardium, promoting left ventricular fibrotic remodeling and dilation.”