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Cardiomyopathy in limb girdle muscular dystrophy R9, FKRP related
Eric M Libell1, Julia A Richardson1, Katie L Lutz1
1Department of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA.
Muscle & Nerve
|September 11, 2020
Summary
Cardiomyopathy affects nearly half of limb girdle muscular dystrophy R9 patients. Those with the c.826C>A mutation experience later onset, aiding future cardiac management.
Area of Science:
- Neurology
- Cardiology
- Genetics
Background:
- Limb girdle muscular dystrophy R9 (LGMDR9) is a genetic disorder with variable reported frequencies of cardiomyopathy.
- Understanding the prevalence and timing of cardiac involvement is crucial for patient management.
Purpose of the Study:
- To determine the frequency and age of onset of cardiomyopathy in a cohort of LGMDR9 patients.
- To investigate the relationship between specific genotypes and cardiac outcomes.
Main Methods:
- Retrospective review of echocardiograms from 56 LGMDR9 subjects.
- Survival analysis was used to assess the cumulative probability of abnormal echocardiograms by age and genotype.
- Correlations between cardiac function (ejection fraction) and clinical measures (10-Meter Walk Test, forced vital capacity) were evaluated.
Main Results:
- Cardiomyopathy was present in 45% (25/56) of the participants.
- The median age of first abnormal echocardiogram was significantly later for subjects homozygous for the c.826C>A variant (54.2 years) compared to other FKRP genotypes (18.1 years).
- A weak correlation was observed between ejection fraction and 10-Meter Walk Test speed, but not with forced vital capacity.
Conclusions:
- Cardiomyopathy is a prevalent complication in LGMDR9.
- Subjects homozygous for the c.826C>A mutation experience a later onset of cardiomyopathy.
- These findings are valuable for guiding surveillance and management strategies for LGMDR9 patients.
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