Reduced muscular carnosine levels in patients with Proximal Myotonic Myopathy (PROMM) - an 1H-MR spectroscopy study

Motivation: Proximal Myotonic Myopathy (PROMM) causes progressive muscle atrophy, particularly affecting fast-twitch Type-2 fibers due to myotonia. Carnosine, essential for Type-2 fiber metabolism, declines with fiber atrophy, making it a potential marker for disease monitoring. Goal(s): This pilot study aims to evaluate carnosine differences in the leg muscles of PROMM patients versus healthy controls using 1H-MR spectroscopy. Approach: 1H-MR spectra were acquired from the left m. rectus femoris of nine PROMM patients and nine healthy controls, quantifying carnosine and other metabolites. Results: PROMM patients exhibited significantly lower carnosine levels and increased extracellular lipids, correlating with muscle mass loss. Impact: This study demonstrates 1H-MR spectroscopy's potential for non-invasive monitoring of PROMM-related metabolic changes by tracking carnosine concentration declines in skeletal muscle. This approach allows early detection of atrophy, supporting personalized disease management and guiding therapeutic interventions.