Mitochondrial Cardiomyopathy: Distinctive Cardiac Phenotype Detected with Cardiovascular MRI

Area of Science:

• Cardiology
• Genetics
• Radiology

Background:

• Left ventricular hypertrophy (LVH) presents a wide differential diagnosis.
• Mitochondrial DNA (mtDNA) pathogenic variants are an uncommon etiology of LVH.
• Cardiac magnetic resonance (CMR) imaging is crucial for diagnosing rare causes of cardiac conditions.

Observation:

• This case report details three siblings harboring a pathogenic variant in the mitochondrially encoded tRNA isoleucine (MT-TI) gene.
• A distinct cardiac phenotype was identified using cardiac MR imaging.
• All three siblings exhibited a consistent pattern of extensive LVH, cardiac dilatation, and reduced ejection fraction.

Findings:

• Cardiac MRI demonstrated increased T2 signal and widespread late gadolinium enhancement in affected siblings.
• The observed cardiac phenotype was remarkably uniform across the three affected individuals.
• Genetic analysis confirmed a pathogenic variant in the MT-TI gene as the underlying cause.

Implications:

• This case highlights the role of cardiac MRI in identifying rare inherited cardiomyopathies.
• Understanding this specific MT-TI gene variant's cardiac manifestation aids in diagnosis and management.
• Early identification of genetic cardiomyopathies through advanced imaging can guide personalized treatment strategies.