Whole-Body Skeletal Muscle MRI Patterns in Female Dystrophinopathy Carriers

Area of Science:

• Genetics
• Neurology
• Radiology

Background:

• Dystrophinopathies result from Duchenne muscular dystrophy (DMD) gene variants, affecting males primarily.
• Female DMD carriers can exhibit variable symptoms, with severe cases classified as dystrophinopathy.
• Asymptomatic female carriers represent a distinct group requiring characterization of subclinical muscle changes.

Purpose of the Study:

• To compare muscle structure in asymptomatic female DMD carriers versus healthy controls using whole-body MRI (WB-MRI).
• To correlate WB-MRI findings with clinical and genetic data in female DMD carriers.
• To identify potential subclinical muscle involvement in female DMD carriers.

Main Methods:

• Cross-sectional observational study comparing 29 female DMD carriers with 30 healthy noncarrier controls.
• Whole-body MRI (WB-MRI) assessed muscle edema, trophism, and fatty infiltration using qualitative grading scales.
• Genetic screening, X-chromosome inactivation studies, neurologic exams, and serum creatine kinase measurements were performed on carriers.

Main Results:

• All 29 female DMD carriers displayed muscle involvement on WB-MRI, compared to 27% of controls (p < 0.001).
• Edema, fatty infiltration, and atrophy were significantly more prevalent in DMD carriers (p < 0.001).
• Calves, thighs, and pelvic region muscles, including gastrocnemius, gluteus maximus, and soleus, were most affected.

Conclusions:

• Asymptomatic female DMD carriers exhibit subclinical muscle abnormalities detectable by WB-MRI.
• These findings suggest a risk of future muscle symptom development in female DMD carriers.
• Multidisciplinary surveillance is crucial for early detection and management of potential complications in female DMD carriers.