A team of researchers from Japan presented the case of a 56-year-old woman with heart failure who did not respond to medications. The patient was diagnosed with X-linked dilated cardiomyopathy based on her family history, myocardial histopathology, and genetic analysis.
The researchers concluded that thorough family history interviews and an investigation of dystrophinopathy are necessary to detect X-linked dilated cardiomyopathy in women and that a differential diagnosis of the condition should be considered before a diagnosis of idiopathic dilated cardiomyopathy is reached.
The team, led by Yuichiro Maekawa, MD, PhD, from the Department of Cardiology, Internal Medicine 3, Hamamatsu University School of Medicine in Japan, reported that even though the patient did not have a skeletal muscle disorder, the family history interviews revealed that there were men in her family who had died of Duchenne muscular dystrophy (DMD).
Read more about the complications of DMD and other muscular dystrophies
Based on this knowledge, myocardial histopathology was conducted. It showed that the patient had low levels of dystrophin protein expression in the membranes of her cardiomyocytes. This was followed by genetic testing, which showed a duplication in exons 8 and 9 of the DMD gene. The patient was diagnosed with X-linked dilated cardiomyopathy based on these findings.
The case study is published in Internal Medicine.
DMD is an X-linked genetic disorder caused by mutations in the DMD gene. This gene provides the instructions necessary to make the dystrophin protein. Dystrophin acts as a shock absorber during muscle contraction, and in its absence, muscle tissue deteriorates and is replaced by scar and fat tissue. The disease affects both the skeletal and cardiac muscles.
Because it is an X-linked disorder, DMD does not usually affect women. However, female carriers of the disease can display some milder symptoms and in rare cases have dilated cardiomyopathy-like cardiac dysfunction.
Ohtani H, Saotome M, Sakamoto A, Suwa K, Maekawa Y. Drug-refractory heart failure in female carrier of Duchenne muscular dystrophy: a case of X-linked dilated cardiomyopathy. Intern Med. Published online November 30, 2022. doi:10.2169/internalmedicine.0745-22