This category encompasses a heterogeneous group of diseases that develop as a consequence of alterations in proteins located in the mitochondria. These proteins are encoded both by the genes present in the mitochondrial DNA and by nuclear genes.
Their wide clinical presentation spectrum ranges from more severe forms of mitochondrial disease, which generally present during infancy or early childhood, to milder forms usually diagnosed during adulthood. Although some of them affect isolated organs, a multisystem presentation is more frequent and involves neurological, metabolic, myopathic, and cardiac manifestations, among others.
Cardiac manifestations typical of mitochondrial disease encompass hypertrophic, dilated, and non-compaction cardiomyopathy and cardiac arrhytmias, including cardiac conduction disorders (AV blocks). Sudden death is also part of this spectrum. Since mitochondrial diseases often present as a syndrome with multiorgan dysfunction, they may not appear to be cardiovascular-specific diseases; moreover, overlapping clinical pictures where the diagnosis of a mitochondrial disease is complex are also observed, and forms that present with isolated cardiac involvement have even been reported.
