Affiliation:
1. Department of Physical Therapy University of Florida Gainesville Florida USA
2. Division of Pulmonology, Department of Pediatrics at the time of the study University of Florida Gainesville Florida USA
3. Division of Pediatric Neurology, Department of Pediatrics University of Florida Gainesville Florida USA
4. Department of Physiology and Aging University of Florida Gainesville Florida USA
Abstract
AbstractIntroduction/AimsThe dystrophinopathies primarily affect males; however, female carriers of pathogenic dystrophin variants can develop skeletal muscle symptoms. This study aimed to evaluate muscle involvement and symptoms in females with dystrophinopathy using quantitative magnetic resonance imaging (MRI), functional assessments, and patient‐reported outcomes.MethodsControls and females with dystrophinopathy with muscle symptoms of pain, weakness, fatigue, or excessive tightness were enrolled in this cross‐sectional study. Participants underwent lower extremity MRI to quantify muscle inflammation, replacement by fat, and disease asymmetry. Cardiac MRI, functional ability, muscle symptoms, and serum creatine kinase levels were also evaluated.ResultsSix pediatric females with dystrophinopathy (mean age: 11.7 years), 11 adult females with dystrophinopathy (mean age: 41.3 years), and seven controls enrolled. The mean fat fraction was increased in females with dystrophinopathy compared to controls in the soleus (0.11 vs. 0.03, p = .0272) and vastus lateralis (0.16 vs. 0.03, p = .004). Magnetic resonance spectroscopy water T2, indicative of muscle inflammation, was elevated in the soleus and/or vastus lateralis in 11 of 17 individuals. North Star Ambulatory Assessment score was lower in the dystrophinopathy group compared to controls (29 vs. 34 points, p = .0428). From cardiac MRI, left ventricle T1 relaxation times were elevated in females with dystrophinopathy compared to controls (1311 ± 55 vs. 1263 ± 25 ms, p < .05), but ejection fraction and circumferential strain did not differ.DiscussionSymptomatic females with dystrophinopathy quantitatively demonstrate muscle replacement by fat and inflammation, along with impairments in functional ability and cardiac function. Additional research is needed to evaluate how symptoms and muscle involvement change longitudinally.
Funder
Parent Project Muscular Dystrophy
University of Florida
National Institutes of Health