Heart failure & cardiomyopathies
Skeletal Muscle Involvement in Patients With Truncations of Titin and Familial Dilated Cardiomyopathy
Authors' conclusion
Mild skeletal muscle involvement was prevalent in patients with TTNtv. The phenotype was characterized by an increased muscle fat fraction and excessive accumulation of glycogen, possibly due to reduced autophagic flux.
Study context
- Population
- Participants with truncating titin variants (19 with dilated cardiomyopathy (DCM)); 11 women, mean age 51 ± 15 years, LVEF 45% ± 10%25 TTNtv participants
- Exposure
- TTNtv vs healthy controls and non-TTNtv genetic DCM controls
- TTNtvn = Twenty-five
- Healthy controlsn = 25reference
- Non-TTNtv genetic DCMn = 7reference
- Outcome
- Skeletal muscle fat fraction by MRI
Main finding
As reported in the abstract
Skeletal muscle fat fraction (MRI)
Difference, % (95% CI)P value
TTNtvvs Healthy controls
2.5(1.4–3.7)
P < 0.001TTNtvvs Non-TTNtv genetic DCM
1.5(0.2–2.8)
P = 0.025Observational data: associations, not effects.
Further findings
Muscle strength (dynamometry)
- Muscle strength within 1 SD of normal values
Myopathic features on muscle biopsy (21 participants biopsied)
- Myopathic features, incl. central nuclei, in 13 of 21 biopsied
- 13 (62%)
Electron microscopy
- Well-ordered Z-lines and T-tubuli; uneven, discontinuous M-lines; excessive glycogen depositions flanked by autophagosomes, lysosomes and abnormal mitochondria with mitophagy
Original publication
Skeletal Muscle Involvement in Patients With Truncations of Titin and Familial Dilated Cardiomyopathy. JACC Heart Fail. Published 22 November 2023. doi:10.
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